GB2461559A

GB2461559A - Pressure balancing cutting chamber for a hover mower

Info

Publication number: GB2461559A
Application number: GB0812224A
Authority: GB
Inventors: Miles Roland William Bozeat
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-07-04
Filing date: 2008-07-04
Publication date: 2010-01-06
Also published as: GB0812224D0

Abstract

The mower includes a cutting chamber 1 and a fan 2 which co-exist with an airflow constraining close running tolerance. The fan has cut-outs 3 disposed around the perimeter thereof. High pressure air flows 4 generated by the fan provide a hover effect to the mower. Part of the high pressure airflows are diverted into the cutting chamber through gaps 5 created by the cut-outs as a result of being drawn into low pressure airflows 6 generated by the rotational action beneath upturns 7 of cutter blades 8. The arrangement ensures that the high pressure air generated by the fan balances the low pressure air generated in the cutting chamber to ensure that the mower is not drawn down into a lawn.

Description

Improvements to Hover mowers-Pressure Balancing Cutting Chamber This invention is art improvement to grass collecting hover mowers that exercise the inventions embodied within either or both of patents Nos GB 2284736 Cut grass collecting hover mower / GB 2298775 Grass Cuttings collection.

Currently all Hover mowers that exercise the inventions embodied within Patent Nos Nos GB 2284736 Cut grass collecting hover mower / GB 2298775 Grass Cuttings collection are characterised by a cutting chamber and a hover generating fan with close running tolerances to the cutting chamber that effectively isolate the high pressure airflow providing the hover outside the cutting chamber from the low pressure airfiows within the cutting chamber except at the perimeter junction of the cutting chamber with the lawn where a balancing and equalising of pressures becomes possible.

Whilst normally this is a satisfactory arrangement under conditions where the grass to be cut is lush or long an effective seal may created at the perimeter junction of the cutting chamber with the lawn so preventing any pressure balancing or equalising of the low pressure airfiows within the cutting chamber with the high pressure airflow providing the hover outside the cutting chamber.

Under the above conditions the unbalanced and unequalised low pressure in the cutting chamber creates a partial vacuum overpowering the high pressure hover air flows so drawing the mower down into the lawn and inhibiting its progress.

It is to this undesirable condition that the present invention provides a solution.

According to the present improving Pressure Balancing Cutting Chamber invention means are provided wherein high pressure air generated by the fan and providing the hover to a mower is allowed passage into the cutting chamber wherein it balances or equalizes the low pressure air generated within the cutting chamber by the high speed passage of the upturn on the cutter blades. The means provided consist of gaps or penetrations being configured into the fan or cutting chamber and br a partial or complete wide running tolerance between the perimeter of the hover generating fan and the inner cutting chamber roof and I or a non circular configuration of the either of the perimeters of the fan and br cutting chamber or combination of same. The extent of the gaps or penetrations required for effective operation of the mower is determined by experiment within a given machine.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which Figure 1 shows in sectional perspective the operative elements of a mower.

Figure 2 shows in section the operative airfiows and pressure areas of a mower.

In this example and referring to the drawings the present improving Pressure Balancing Cutting Chamber invention subsists within a hover mower exercising both and br either of the inventions as described in patent Nos Nos GB 2284736 Cut grass collecting hover mower / GB 2298775 Grass Cuttings collection. A cutting chamber I and a fan 2 co-exist with a airflow constraining close running tolerance. The said fan 2 has cut-outs 3 disposed around the perimeter. High pressure air flows 4 generated by the said fan 2 to provide the hover to the mower. Part of said high pressure airflows 4 are diverted into the said cutting chamber I through gaps 5 created by said cut-outs 3 as a factor of being drawn in by the low pressure airfiows 6 generated by the rotatational action beneath the upturns 7 of the cutter blades 8. The extent of the said gaps 5 required for effective operation of the mower is determined by experiment within a given mower.

The said gaps 5 may be supplemented or replaced by a non air flow constraining running tolerance between said cutting chamber I and said fan 2 and / or through penetrations in either or both of the said fan 2 or the said cutting chamber I [ for clarity not illustrated in this example].

Claims

CLAIMSI. The present improving Pressure Balancing Cutting Chamber invention subsists within a hover mower exercising both and br either of the inventions as described in patent Nos A Nos GB 2284736 Cut grass collecting hover mower / GB 2298775 Grass Cuttings collection. A cutting chamber I and a fan 2 co-exist with a airflow constraining close running tolerance. The said fan 2 has cut-outs 3 disposed around the perimeter. High pressure air flows 4 generated by the said fan 2 to provide the hover to the mower. Part of said high pressure airfiows 4 are diverted into the said cutting chamber I through gaps 5 created by said cut-outs 3 as a factor of being drawn in by the low pressure airfiows 6 generated by the rotatational action beneath the upmrns 7 of the cutter blades 8. The extent of the said gaps 5 required for effective operation of the mower is determined by experiment within a given mower.
2. An improving Pressure Balancing Cutting Chamber as claimed in labove wherein the said gaps may be supplemented or replaced by a non air flow constraining running tolerance between cutting chamber 1 and fan 2
3. An improving Pressure Balancing Cutting Chamber as claimed in labove wherein and the said gaps 5 may be supplemented or replaced by through penetrations in either or both of the said fan 2 or the said cutting chamber 1.