GB2280837A

GB2280837A - A lawnmower with an indicator for indicating when grassbox is full

Info

Publication number: GB2280837A
Application number: GB9315251A
Authority: GB
Inventors: Peter John Kirton
Original assignee: Electrolux Outdoor Products Ltd
Current assignee: Husqvarna UK Ltd
Priority date: 1993-07-23
Filing date: 1993-07-23
Publication date: 1995-02-15
Anticipated expiration: 2013-07-23
Also published as: GB9315251D0; GB2280837B

Abstract

A grass collector for a lawnmower, the grass collector including a container for receiving cut grass and an indicator F for indicating at least when the collector requires to be emptied, the indicator including a displaceable element which is displaceable into a position indicating at least when the collector requires to be emptied in response to a difference in air pressure existing between air pressure within the container and ambient air pressure. <IMAGE>

Description

A LAWNMOWER WITH AN INDICATOR FOR INDICATING WHEN GRASSBOX IS FULL This invention relates to grass collectors for lawnmowers and to lawnmowers including such collectors.

In particular the grass collector includes an indicator for indicating at least when the collector requires to be emptied.

Conventional lawnmowers often have fully enclosed grass collection boxes for collecting grass cut by the mower. Certain lawnmowers have cutter member rotatably mounted in a cutting chamber for cutting the grass, and a source of pressure air which carries the grass cut by the cutter member through a duct and into the grass collector. The grass container is typically a perforated bag or a metal box.

The source of pressure air may be the cutter member itself or in combination with an impeller. In the case of a rotary mower, the blades may have upturned tips and the impeller is coaxially driven with the blade. In the case of a cylinder mower, the cylinder blades may generate a flow of air. Furthermore, the blades may impart momentum to the cut grass assisting in its passage to the grass container.

The source of pressure air may also apply suction to the duct at an upstream end thereof. The duct therefore draws grass cuttings into the grass container.

During operation of such mowers, it is frequently difficult for a user to know when the grass collector is full and continued operation results in cut grass being left on an otherwise mown lawn. This is caused when the duct becomes blocked. Such blockage may also adversely affect the cutting blade in that the cutting chamber may also become blocked with compressed grass cuttings.

Clearing a blocked duct or cutting chamber is time consuming and necessitates switching off all power to the mower in order to avoid injury to the operator. Furthermore, such clearance invariably leaves grass strewn on the lawn requiring subsequent collection.

At present the only certain way of checking whether the grass container is full is to remove the same and visually check the quantity of grass in the collector.

Another way is to feel the level of grass cuttings but this technique is only applicable where the collector is made from a fabric.

It is an object of this invention to overcome or at least reduce the disadvantages and difficulties outlined above.

According to the present invention a grass collector for a lawnmower includes a container for receiving cut grass and an indicator for indicating at least when the collector requires to be emptied, the indicator including a displaceable element which is displaceable into a position indicating at least when the collector requires to be emptied in response to a difference in air pressure existing between air pressure within the container and ambient air pressure. Preferably, the collector includes a guide for guiding displacement of the displaceable element into a position indicating at least when the collector requires to be emptied. Conveniently, the guide includes a tubular housing having a first aperture in communication with the interior of the container and a second aperture in communication with ambient air. According to one embodiment of the invention the displaceable element is a float displaceable between the first and second apertures which are formed to restrain passage of the float therethrough.

The invention also includes a lawnmower having a collector as described above.

The collector according to the present invention is suitable for use with any form of lawnmower, for example, mowers including cylindrical cutters, single or multibladed rotary mowers which may be supported by wheels or by a cushion of air or a combination thereof.

Where the collector is used with a rotary mower, the mower preferably includes a source of pressure air, at least a part of which is used for entraining and transporting cut grass into the container. In such cases, the different in air pressure decreases during progressive filling of the container.

The invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a diagrammatic section of a first form of grass collector in accordance with the invention; Figure 2 is a diagrammatic section to an enlarged scale of one form of indicator encircled and designated "Z" in Figure 1; Figure 3 shows an alternative form of indicator.

Referring to Figure 1 a grass collector A has a container 1 which is divided into a grass recovery portion B and an air space C by a filter D. The filter D serves to prevent, or at least reduce, passage of cut grass into the air space C. The container also includes a vent E to atmosphere.

As indicated above, the grass collector according to the invention is particularly suitable for use with a lawnmower including a source of pressure air at least a part of which is used for entraining and transporting cut grass into the container. For such a mower grass entrained in a stream of pressure air enters the container 1 via an inlet 6 which may extend towards the filter D.

Alternatively, the inlet 6 may be positioned at one end of the grass collector 1 and indicated at X for direct communication with a chute which opens into a cutting chamber of a rotary mower.

In operation of the collector of Figure 1 and as the level of grass cuttings 3 in the container 1 rises, the pressure of air in the air space C decreases. A changing differential air pressure will therefore exist between the pressure within the container 1 and ambient atmosphere.

This differential air pressure is used to operate an indicator for indicating to an operator when the grass collector should be emptied.

The indicator shown in Figure 1 has a tubular housing H which may be integral or separate from the container.

The tubular housing has two oppositely disposed apertures Hi and H2 leading into the container 1 and to atmosphere respectively. Located within the housing is a float F in, for example, the form of a spherical ball which is freely movable within the tubular housing H.

In operation, and at start up the differential air pressure between the interior of the container 1 and atmosphere is relatively high since the container 1 is empty and the float is urged towards the aperture H2.

During use and, consequently, filling of the container with grass cuttings, the pressure differential progressively decreases. The size and weight of the float F are such that when the container is full and requires emptying, the float F falls towards the aperture H2 to give a positive visual indication to the operator.

Referring to Figure 2 (where like components are designated by like reference numbers to those used in Figure 1), the float F of Figure 1 is replaced by a modified indicator. The indicator of Figure 2 has two interconnected divergent flaps J1 and J2 of different lengths and mounted for angular displacement about an axis K in the region of their inter-connection. A window W is formed in the wall of the tubular housing H. According to the angular position of the flap J2 the window is either covered or uncovered.

The position of the flaps J1 and J2 is again determined by the differential air pressure existing between the inside of the container 1 and atmosphere. At start-up the indicator is in the full line position shown in Figure 3. During filling the pressure differential continually decreases and the indicator is progressively angularly displaced counter-clockwise and under its own weight until, when the container 1 requires to be emptied, the flap J2 covers the window W. The operator is, therefore, made visually aware that the container should be emptied.

Although in the embodiments described with reference to Figures 1 and 2 the indicator operates to afford a visual indication when the pressure differential between the pressure within the container and atmosphere decreases, the indicator may also be operated in the reverse manner when the pressure differential increases or by regulating the position of the indicator according to the pressure in a positive pressure line in communication with the source of pressure air in the mower.

Claims

CLAIMS:

1. A grass collector for a lawnmower, the grass collector including a container for receiving cut grass and an indicator for indicating at least when the collector requires to be emptied, the indicator including a displaceable element which is displaceable into a position indicating at least when the collector requires to be emptied in response to a difference in air pressure existing between air pressure within the container and ambient air pressure.

2. A collector according to claim 1 including a guide for guiding displacement of the displaceable element into a position indicating at least when the collector requires to be emptied.

3. A collector according to claim 2, wherein the guide includes a tubular housing having a first aperture in communication with the interior of the container and a second aperture in communication with ambient air.

4. A collector according to claim 3, wherein the displaceable element is a float displaceable between the first and second apertures which are formed to restrain passage of the float therethrough.

5. A collector according to claim 3 or claim 4, wherein the tubular housing is disposed substantially vertically within the container.

6. A collector according to any one of claims 2 to 5, wherein the guide is a channel having a first aperture in communication with the interior of the container and a second aperture in communication with ambient air.

7. A collector according to claim 6, wherein the channel is disposed at an angle inclined to the vertical within the container.

8. A collector according to any preceding claim wherein the indicator is removably mounted within the container.

9. A collector according to any preceding claim for use with a lawnmower including a source of pressure air at least a part of which is used for entraining and transporting cut grass into the container and wherein the said difference in air pressure decreases during progressive filling of the container.

10. A collector according to claim 4, wherein the float is substantially spherical.

11. A collector according to claim 1, 2 or 3, wherein the tubular housing includes a window visible by an operator and wherein the displaceable element includes a flap mounted for displacement to cover and uncover at least a portion of the window.

12. A collector according to claim 11, wherein the displaceable element includes two interconnected and divergent flaps, means for supporting the flaps for angular displacement about an axis in the region of their interconnection and wherein at least one flap is subjected, in use, to the said difference in air pressure thereby creating angular displacement of the other flap to cover and/or uncover at least a portion of the window.

13. A collector according to claim 12, wherein one flap is displaceable to cover and/or uncover the window and the other flap is displaceable to cover and/or uncover the second aperture in communication with ambient air.