GB2108815A

GB2108815A - Grass receptacle for an air cushion mower

Info

Publication number: GB2108815A
Application number: GB08230940A
Authority: GB
Inventors: Ian Charles Abel; Graham Davison Turner
Original assignee: Flymo Ltd
Current assignee: Flymo Ltd
Priority date: 1981-11-11
Filing date: 1982-10-29
Publication date: 1983-05-25
Also published as: FR2515924A1; SE8106702L; DE3239205A1; SE428749B; FR2515924B1; JPS5889112A; DE3239205C2; CA1206931A; JPH0372242B2; GB2108815B

Abstract

An air cushion mower has a grass collecting receptacle (11) supported at least partly by a separate air cushion. The receptacle (11) is suitably a flexible bag having a lower horizontal surface (27) provided with holes (31) so that, in use, air may pass from the bag into chamber (30). <IMAGE>

Description

SPECIFICATION Grass receptacle for an air cushion mower This invention relates to a grass receptacle for an air cushion mower.

Air cushion lawn mowers are known and usually comprise a hood supporting an electric motor or an internal combustion engine. The engine or motor rotates a vertical shaft to which a fan is fastened under the hood and this fan creates an air cushion under the hood by drawing air from the atmosphere through an opening into the hood. The lower end of the shaft has a rotatable blade which cuts the grass. It is also known to provide this type of lawn mower with a grass collecting receptacle, see British Patent No.

997,528 and British Patent Application No.

2,017,475. The patent application shows a device which has proved satisfactory in operation aithough the fact that it takes away a part of the air from the air cushion in order or transfer the grass clippings from the area of the blade to the collecting receptacle creates a problem. This problem has been solved by giving the mower a special shape.

A drawback of arrangements of the type described above is that the weight of the collected grass in the receptacle influences the air cushion unfavourably and thus also the handling of the mower, in particular when the receptacle is filled with wet grass. This in turn means that the collecting capacity of the receptacle will not be very great.

According to this invention an air cushion mower has a grass collecting receptacle which is at least partly supported by an air cushion. Also according to this invention there is provided a grass collecting receptacle for an air cushion mower, wherein the grass receptacle is wholly or partly supported by an air cushion.

An embodiment of the invention will now be described by way of example with reference to the drawings, in which: Fig. 1 is a part vertical section; and Fig. 2 shows a mower and receptacle seen from below.

Referring to the drawings, an air cushion mower 10 has a grass collecting receptacle 11 connected to it. The mower 10 comprises a hood 12 having an outer peripheral lip 13 and a central inlet 14 for air and also an outlet 15 for cut grass.

The outlet 1 5 is, when the mower is used without the grass receptacle, covered by a lid 1 6 which is turnable about a horizontal axis 1 7. The mower also has a motor 18 mounted on a support 19 in the centre of the air inlet 14. The motor shaft supports a fan wheel 20 and a knife blade 21, which, with spacers 22, are fastened to the shaft at a desired distance above ground by means of a bolt 23. At the lower rear part of the hood is a deflecting plate 24 directing the air stream and grass clippings towards the outlet 1 5.

During rotation of the motor shaft an air cushion is created under the hood by the fan which makes the hood float above the ground. At the same time the knife blade rotates thus cutting the grass and transporting it by the air stream toward the outlet 1 5.

The fan wheel 20 in this embodiment is a combined axial and radial fan having a circular bottom plate which is fastened by a central part to the motor shaft. The bottom plate has a number of vertical radial fan blades covered by an annular wall, the bottom plate, wall and blades together forming a radial fan. The peripheral fan part of the annular wall supports a number of axial fan blades running in the inlet 14. Cooling air is drawn through the motor by the radial fan blades, and this air is forced into the air cushion together with air drawn into the cushion by the axial fan blades through the opening 14.

The grass receptacle 11 in this diameter is a bag 25 of flexible material and which has an inlet 26 surrounded by a stiff member for connection and locking to the outlet 1 5 of the mower. The bag 25 is divided by a horizontal surface 27 divided from a lower rigid part 28, which has a lip 29, similar to the peripheral lip 13 of the mower.

The lip extends along three of the four sides of the bag. When the bag is connected to the mower a chamber 30 is formed below the horizontal surface 27 and between the rear lip part of the mower and the lip 29 of the lower part 28 of the grass bag. The horizontal surface 27 has a number of holes 31, making it possible for air to pass from the grass bag into the chamber 30.

The mower has the usual handle and cover for the motor, not shown.

The device operates in the following manner.

During rotation of the motor shaft grass is transported into the grass collecting bag, partly by the throwing effect of the knife, and partly by the air stream caused by the fan wheel, thereby taking up the grass being cut by the blade 21 and transferring it through the outlet 1 5 into the bag 25. In the bag, the air stream is turned downwards and passes through the holes 31 into the chamber 30, leaving the grass clippings on the horizontal surface 27. Simultaneously air leaving the hood below the rear part of the lip 13 is transferred into the air cushion of the bag. Thus, in the chamber 30 an air cushion is created which keeps the bag floating together with the mower.

When the bag gradually fills with grass clippings the holes 31 in the horizontal surface 27 become obstructed, thus preventing air from the air cushion, together with grass clippings, reaching the chamber 30. The air cushion under the grass bag is then mainly created by the flow of air from the rear part of the lip 13.

It is possible to use other types of grass receptacle, for example of rigid material, and to use other arrangements in the lower part 28 of the receptacle, for example a hinging, a flexible or an articulating element. It is also possible to provide the upper part of the grass receptacle with openings through which air leaves to atmosphere in order to improve the transport of grass clippings to the receptacle when the holes in the bottom of the receptacle have become obstructed, although such a leakage negatively affects the air cushion.

Claims

1. An air cushion mower having a grass collecting receptacle which is at least partly supported by an air cushion.

2. A grass collecting receptacle for an air cushion mower, wherein the grass receptacle is wholly or partly supported by an air cushion.

3. A receptacle according to claim 2, wherein the air cushion of the receptacle is created by air from the air cushion of the mower.

4. A receptacle according to claim 3, wherein the air for the air cushion of the receptacle assists transport of grass into the receptacle.

5. A receptacle according to any of claims 2 to 4, wherein the receptacle has at its lower part a peripheral wall whose lower portion forms a lip which, when the receptacle is fastened to the mower, is situated mainly in the same horizontal plane as the corresponding part of the mower.

6. A receptacle according to claim 5, wherein the said peripheral wall is rigid.

7. A receptacle according to claim 5 or claim 6 wherein the upper part of the peripheral wall has a substantially horizontal, holed surface or grating on which grass clippings are collected.

8. A receptacle according to any of claims 5 to 7, wherein the part of the receptacle situated above the lower peripheral wall is made of flexible material.

9. A receptacle according to any of claims 2 to 8, wherein air is transferred from the mower to the receptacle through a substantially upright vertical opening in the upper part of the receptacle in which part the grass is separated and the main part of the air is led downwards through openings to the air cushion under the receptacle whence is escapes to atmosphere.

10. a receptacle according to any of claims 2 to 9, wherein the mower has a combined radial and axial fan wheel for establishing the air cushion.

11. A receptacle according to claim 10, wherein the radial fan wheel part draws cooling air for the motor into the air cushion whereas the axial fan wheel part draws air directly from atmopshere to the air cushion.

12. An air cushion mower grass collecting receptacle constructed and arranged substantially as herein described and shown in the drawings.

13. An air cushion mower having a grass collecting receptacle according to any of claims 2 to 12.