GB2292663A - Rotary lawnmowers - Google Patents

Description

1 ROTARY LAWNMOWERS 2292663 The present invention concerns a rotary

lawnmower of the type that is supported on a cushion of air and is commonly known as a "hovermower". In particular, the invention concerns a hovermower in which a motor is supported on a deck for driving a cutter and a fan about a vertical axis in an open-bottomed plenum chamber formed beneath the deck. The cushion of air supporting the mower is then formed beneath an outwardly extending upturned rim of the deck, the rim also acting as a protective buffer when manoeuvring the mower over the ground. Without such a rim, the performance of the hovermower is adversely affected.

A disadvantage of the upturned rim is that it creates a trough in the upper surface of the deck that collects grass cuttings and other debris when mowing a lawn.

Accordingly, cleaning and maintenance of the mower is hampered because the grass cuttings and debris that collect in the trough can be removed effectively only by inverting the entire mower.

Grass collecting hovermowers may include an upper moulding which covers the underdeck and conceals the trough formed by the upturned rim, but these mowers are generally bulky and more difficult to manoeuvre.

According to the present invention, a hovermower deck that comprises an open bottomed plenum chamber formed with an outwardly extending upturned rim further comprises a peripheral trim extending outwardly from a sidewall of the plenum chamber to bridge the trough created in the deck by the upturned rim.

With a moulded deck, the trim can be formed as part of the moulding process, but in a preferred embodiment the trim is a separate component engageable with the upturned rim of the moulded deck.

With the trim fitted, the trim surface preferably extends from a position substantially flush with a top surface of the plenum chamber. In this manner, a smooth continuous 2 downwardly sloping surface is formed around the outside of the plenum chamber and any grass cuttings falling on the surface will tend to slide off.

In the accompanying drawings, by way of example only:

Fig. 1 is a perspective sketch of a lawnmower embodying the invention; and Fig. 2 is a part transverse vertical section through the mower.

Referring to these drawings, a hovermower 10 is illustrated having a motor housing 11 protecting a motor 40 driving a fan 12 and a cutter 13 about a common vertical axis. The cutter and the fan rotate in a plenum chamber 14 having a domed roof 15 and a peripheral sidewall 16 which together form a deck or shroud protecting the rotating cutter. 15 The hovermower is manoeuvred over the ground by a handle 34 pivotally supported in handle brackets 35 secured to the deck.

The bottom of the sidewall 16 is formed with an outwardly extending upturned rim or skirt 17. The cushion of air produced by the fan 12 and supporting the mower is formed between this upturned rim or skirt and the ground. 'Me upturned rim or skirt also acts as a protective buffer when manoeuvring the deck over the ground, the deck being formed of a strong, rigid plastics material such as ABS.

A peripheral trough 18 created in the top surface of the deck by the upturned rim 17 is covered and concealed by a trim component 19 engageab.le with the upturned rim.

The trim 19 is formed of a more flexible plastics material, such as polypropylene.

The trim 19 has a tongue 20 supported on a recessed ledge 21 in the roof 15 of the plenum chamber 14, and has a curved external surface 22 extending outwardly and downwardly from the tongue 20 to abut the outermost portion 23 of the upturned rim 17. The curved surface 22 is therefore flush with the roof 15 of the plenum chamber and with the upturned rim 17. In addition, spaced apart fingers 24 (only one being 3 shown in Fig. 2) each having an associated strengthening rib 25 extend downwardly from the surface 22.

The fingers 24 are of variable length commensurate with the variable height of the sidewall 16 around the periphery of the plenum chamber 14, and the length of the ribs is correspondingly varied to ensure that the length of the finger 24 projecting beyond the respective rib is substantially the same for each finger. The fingers 24 therefore have a uniform flexibility. Each finger has a catch 36 at its bottom end, the catch 36 engaging behind a respective resilient latch 26 to engage the trim with the upturned rim 17. The upstanding latch 26 forms the resilient prong of a clip, each clip including an opposed non-resilient prong 27 forming an opening with the prong 26 for receiving the respective fingers. The prongs 26, 27 are formed by upstanding ribs in the upturned rim 17.

To assist alignment of the trim 19 with the upturned rim 17, the upturned rim has guide ribs 29 spaced around its periphery, the ribs 29 each having top and bottom recesses 30, 31 for locating corresponding tongues 32, 33 projecting downwardly from the curved surface 22 of the trim.

The external surface 22 of the trim includes a shallow decorative groove 37.

It can be seen that the clip-on trim 19 not only provides a decorative trim around the periphery of the deck, but it also prevents any grass cuttings or other debris collecting in the trough 18 created by the upturned rim 17. The advantages of providing an upturned rim are therefore retained, while the disadvantages are overcome to provide a deck having an aesthetically pleasing functional configuration.

4

Claims (1)

1. A hovermower comprising: a cutter rotatable about a substantially vertical axis beneath a protective floating deck bounded by an outwardly extending upturned rim, the deck including a raised central portion forming a plenum chamber and a peripheral trim extending outwardly from a sidewall of the plenum chamber to bridge the trough created in the deck by the upturned rim.

2. A hovermower according to claim 1 wherein the trim extends outwardly to the upturned rim from a position substantially flush with a top surface of the plenum 10 chamber.

3. A hovermower according to claim 2 in which the trim cooperates with the top surface of the plenum chamber to form a substantially continuous downwardly sloping surface.

5. A hovermower according to any one of the preceding claims in which the trim is a separate component engageable with the rim of the deck.

7. A hovermower according to claim 6 in which the trim includes a plurality of downwardly extending prongs engageable with respective upstanding clips in the rim of the deck, the prongs being of variable length and uniform flexibility.

4. A hovermower according to any one of the preceding claims in which the trim has an inner edge overlying a recess in the sidewall of the plenum chamber and an outer edge abutting the outermost portion of the upturned rim.

6. A hovermower according to claim 5 in which the trim is clipped to the deck.

8. A hovermower deck comprising an open-bottomed plenum chamber formed with an outwardly extending upturned rim and further comprising a peripheral trim extending outwardly from a sidewall of the plenum chamber to bridge the trough created in the deck by the upturned rim.

9. A hovermower deck according to claim 8 wherein the peripheral trim is formed by a separate component engageable with the upturned rim of the deck.

10. A hovermower deck according to claim 9 wherein, with the trim fitted, the 5 trim surface extends from a position substantially flush with a top surface of the chamber to a position abutting the outermost portion of the upturned rim.

11. A hovermower substantially as herein described with reference to the accompanying drawings.

12. A hovermower deck substantially as herein described with reference to the accompanying drawings.