GB2308049A

GB2308049A - Device for ground care

Info

Publication number: GB2308049A
Application number: GB9625615A
Authority: GB
Inventors: Frank Koelsche; Dietmar Hartmann
Original assignee: Sabo-Maschinenfabrik GmbH; SABO Maschinenfabrik GmbH
Current assignee: Sabo-Maschinenfabrik GmbH; SABO Maschinenfabrik GmbH
Priority date: 1995-12-11
Filing date: 1996-12-10
Publication date: 1997-06-18
Anticipated expiration: 2016-12-10
Also published as: IT1285984B1; ITMI962442A1; GB2308049A8; SE9604452D0; GB9625615D0; GB2308049B; FR2743218A1; ITMI962442A0; DE19546128C2; SE9604452L; DE19546128A1

Description

2308049 Title: DEVICE FOR GROUND CARE

Description of Invention

This invention relates to a device for ground, i.e. landscape, yard, garden or lawn, care, especially but not exclusively a lawn mower, having a housing movable on a surface to be worked, at least one tool drivable so as to rotate around a rotational axis in the housing, and two mechanically connected electric motors fixed to the housing and operable for driving the tool.

Such a device is described in DE-OS-2049609 which discloses a lawn mower which, depending on its application - on a dry lawn on the one hand and a wet lawn on the other hand - has a good overall efficiency, and to this end it is proposed to provide two or more motors ancl that optionally only one motor is used or, if necessary, two or more motors simultaneously for operating the lawn mower. The object is to ensure that, depending on the condition of the lawn, the necessary or desired operating power is made available. The device is designed in such a way that, overall, it can only be operated either by one or all motors, using battery supplied electrical power or niains electrical power. It is thus a classic lawn mower design which is either used as a battery lawn mower or as a lawn mower to be operated by mains electricity.

It is the object of the invention to provide a device for ground care, which is versatile in its application and which, as regards driving its working tools, can be adapted to existing output requirements and which also permits a certain type of operation to be selected.

In accordance with the invention, the objective is achieved in that one of the electric motors is adapted to operate on mains electrical power and the other one is adapted to operate on batterv-supplied electrical power.

The advantaue of this is that, depending on local conditions, the device can be operated either by the mains-powered motor or by the batterypowered motor. Furthermore, the type of operation may also be selected as a function of C 1) the power output requirements which exist. If a high Output is required, the 0 device can be operated by mains power whereas, in the case of low or dry grass, operation by the battery-powered motor is selected. Thus, flexibility results from the possibility Of LISinu the batter -powered motor, i.e. driving the device by 0 y battery, or a higher output can be provided if this is required by local conditions. A cost-effective embodiment is achieved if the mains-powered motor and the battery-powered motor are arranged, one behind the other, on an output shaft which also serves for attachinu tile tool.

As an alternative it is proposed that the mains-powered motor and the bat te ry-powe reel motor may, be arranged side by side and in such a way that their output shafts extend parallel relative to one another, and the output shaft of the mains-powered motor serves for attaching the tool. However, the arrangement of the motors may also be exchanged. With such an arrangement, a mechanical connection between the two motors is easy to achieve.

In the case of a device wherein the working tool rotates around a normal axis, i.e. perpendicularly relative to the ground surface to be worked, on which the device is movable, the two motors may be arranged one above the other.

According to one embodiment of the invention, it is proposed that there may be provided means for changing over from operation by the mainspowered motor to operation by the battery-powered motor. Said means may also serve to prevent the possibility of establishing a connection with the mains electrical supply, and to actuate a switch which is positioned in a circuit between a battery and an operating switch foi- starting or stopping the drive of the operating tool.

This measure ensures that only one of the two motors can be started, with the other one necessarily being excluded frorn being supplied with electrical power. Furthermore, the operating switch which has to be constantly actuated by the operative to continue the operation of the device, retains its function, i.e. that 0 3 it is able to carry out its function both in respect of battery-powered operation and mains-powered operation.

In putting the invention into effect, a particularly advantageous embodiment is achieved if, for supplying mains electrical power, there is provided a socket which is intended to be connected to the plug of a cable connectable to the mains power supply or into which there is insertable a dummy plug which serves changing-over purposes and which, at the same time, serves to actuate the switch, with the switch beine associated with the socket.

Finally, it is proposed that tile output shaft of the mains-powered motor may he connected to the output shaft of the battery-powered motor by means of a belt drive, chain drive or gearwheel drive.

According to a further embodiment, there may be provided switching means by which the mains-powered motor can be braked with the help of the battery-powered motor when opening the operating switch.

Two embodiments of the invention are diagrammatically illustrated in the drawings, wherein:- Figure 1 is a side elevation of a first embodiment of the device in accordance with the invention, in the form of a lawn mower, having a mains current motor and a battery current motor arranged on a joint output shaft; Fi-ure 2 shows a modified embodiment wherein the mains current motor and the battery current motor are arranged parallel relative to one another, with a drivinu connection established therebetween by a belt drive; Figures 3 and 4 shown an electrical connection system of a device in accordance with the invention.

Tile lawn mower illustrated in Figure 1 comprises a housing 1 to which there are attached wheels 2, 3 by means of which the lawn mower is movable on a lawn surface 5 to be worked. For movinu the mower, there is provided a guiding bar 4 which is secured to the housing 1 and which may be held by an operative.

C '\ 4 A mains current electric rnotor 6 and a battery current electric motor 7 are both secured to the housing 1 and arranged one above tile other on the output shaft 8. The rotational axis of the output shaft 8 has been given the reference number 9 and is oriented substantially perpendicularly to the surface 5 to be worked. The output shaft 8 carries a blade bar 10 which rotates around the rotational axis 9 and which, when moved across the lawn constituting the surface 5 to be worked, cuts the grass at the required level.

The mains current motor 6 is supplied with mains current by a cable connected to the mains electrical supply system, with the battery current motor 7 being supplied by a battery 11 which is attached to the housing 1. The material cut by the blade 10 is transferred into a collecting container 12 suspended at the housina 1. For switching the mower on and off, i.e. for starting and stopping the motor selected for driving the mower, there is provided a switching lever 13 which actuates an operating switch 15 through a connecting means 14. The switching lever 13 is provided in the form of a hinged arni which has to be held by the operative in the position indicated by continuous lines to start the motor to be driven. If the mains current motor has been selected for driving purposes, mains electricity is supplied through a connector socket 17 which may be connected to a plue connected to the mains current by means of a cable. The operating switch 15 is arranued in the circuit between the socket 17 and the mains current motor 6. The operating switch 15 is also provided with contacts by rneans of which the connection between the battery current motor 7 and the battery 11 is closed and opened. In addition, said battery circuit includes a further switch 16 which is associated with the socket 17. The switch 16 can be closed only if the socket 17 contains a dummy plug 18 which is provided with means for operating the switch 16. In this way is ensured that the socket 17 is simultaneously inaccessible for a mains plug, i.e the dunimy plug simultaneously serves as a removable safety key when usinu the lawn mower as a battery-operated mower. However, the battery current motor 7 is started and stopped by the switching lever 13 and via the operating switch 15 loaded thereby - 'List as in the case of the mains current c j motor 6. The switching lever 13, if not held by the operative, automatically returns into a position which actuates the operating switch 15 in the sense of interrupting the power circuit.

For both methods of operation, the operations of braking the blade 10 and observing the predetermined blade stoppage time are effected by the battery current motor 7 which is in the form of a D.C. motor. For this purpose, when switching off the device, the battery current motor 7 acts as a brake. However, mechanical braking is also possible. The motors may bc exchanged as far as their positions are concerned.

In the embodiment of the lawn rnower accordino to Figure 2, the output shaft 19 of the battery current motor 7 ' extends parallel to the output shaft 8 ' of the mains current motor 6 '. The output shaft 8 ' comprises an output shaft stub 8 " projecting upwardly from the motor housing. The output shaft stub 8 " and the output shaft 19 of the battery current motor 7 ' are provided with belt pulleys 20, 21 respectively between which a driving connection is provided by a belt 22. The blade 10 ' is arranued oil the output shaft 8 ' of the mains current motor 6 '. Otherwise, the embodiment according to Figure 2, especially, in respect of design and arrangement of tile means for changing over from battery operation to mains operation and vice versa, corresponds to the embodiment described with reference to Figure 1.

Figures 3 and 4, in a simplified way, show a switching system wherein the socket 17 is engaged with a mains plug 23, so that the device is operated by the mains current motor 6 when the operating switch 15 is actuated by the lever 13 by way of the connecting means 14. The switch 16 foichanging over to l 0 0 t> operation by the battery current motor 7 is open. In addition to two contacts for engagement with the two poles of the mains plug 23, the socket 17 comprises a bore 24 extending parallel to the contacts and ending in the region of an operatirlu rnernber 25 of the switch 16. For tile purpose of switching over to operation by the battery current motor 7 - as shown in Figure 4 - the mains plug 213) has to be pulled out of the socket 17 and a dunli-ny plug 18 has to be inserted 0 6 into said socket. The dUmmy Plug 18 comprises an actuating pin 26 which passes throuah the bore 24 when the dummy plug is inserted and actuates the operating member 25, so that the switch 16 closes the circuit from the battery to the battery current motor 7. Then, the operating switch 15 causes the device to be operated by the battery current motor 7.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed fUnction, or a method or process for attaininu the disclosed result, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

7

Claims

1. A device for ground care, especially a lawn mower, having a housing movable on a surface to be worked, at least one tool drivable so as to rotate around a rotational axis in the housinu, and two mechanically connected electric 0 motors and operable for driving the tool fixed to the housing, wherein one of the 0 c motors is adapted to operate oil mains electrical power and the other one is adapted to operate on battery-supplied electrical power.

2.

A device accordino to Claim 1, wherein the mains-powered motor and 0 the batte ry-powe reel motor are arranued, one behind the other, on an output shaft c which also serves for attaching the tool.

3. A device according to Claim 1, wherein the mains-powered motor and the battery-powered motor are arranged side by side, so that their respective 0 output shafts extend parallel relative to one another, and the output shaft of the mains current motor serves for attachinu tile tool.

0

4. A device according to Claim 2 or Claim 3, wherein the output shaft Z:1 associated with the tool extends substantially perpendicularly to the surface to he worked, on which the housing is movable.

5. A device according to any one of the preceding claims, wherein there are provided means for changing over from the mains-powered motor to operation by the battery-powe reel motor and which prevent the possibility of establishing a connection with the mains electrical supply and at the same time actuates a switch which is arranged in a circuit between a battery and an operating switch for starting or stopping the drive of the working tool.

1. 0 W

6. A device according to Claim 5, wherein for supplying mains electrical power, there is provided a socket which. is intended to be connected to the plug of a cable connectable to the mains power supply or into which there is insertable a dummy plug which serves changing-over purposes and which, at the same time, serves to actuate the switch, with the switch beinu associated with the socket.

0

7. A device according to Claim 3, wherein the output shaft of the mains0 powered motor is connected to the output shaft of the battery-powered motor by a belt drive, chain drive or gear wheel drive.

8. A device according to any one of the preceding claims, wherein there 0 c are provided switching means for connecting the battery current motor to operate 0 as a brake when opening the operating switch.

9. A device substantially as hereinbefore described with reference to the accompanying drawings.

0 c

10. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.