GB1598910A - Lown mowers - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO LAWN MOWERS (71) I, GEORGE SOAN, a British Subject, of 3, Chobham Close, Chobham Road, Ottershaw, Surrey, England, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to lawn mowers of the cylindrical type, that is to say mowers in which a plurality of cutting blades helically arranged about a notional cylinder and extending between end members, are caused to rotate about the central longitudinal axis of the notional cylinder whilst the mower is being propelled.

Such cylinder mowers are very efficient but they are notoriously unsuitable for cutting the long coarse grass stalks that frequently occur. Generally speaking, it has been found necessary to employ a rotary mower for cutting such long stalks which operates in effect on the scythe principle, but mowers of this kind have the disadvantage tbat they cannot produce the conventional striped pattern which only a good cylinder mower incorporating a roller can produce.

It is therefore an object of the invention to enable a mower of the cylinder type to be able not only to mow the grass in the conventional pattern, but also to cut the long coarse stalks that project above the normal grass height.

According to the invention at least one of the blades of the cutter assembly of a cylinder mower is provided with at least one aperture of re-entrant shape to entrap and cut off long grass stalks.

Preferably, each blade is provided with a number of such apertures and these are staggered from blade to blade so that if a grass stalk is missed by one blade, it will be cut by another. The apertures may follow a helical path.

Each re-entrant aperture may comprise a straight-sided slot which opens out into an oval or similarly re-entrant shaped aperture and the edges of all or part thereof may be sharpened to enhance the cutting effect.

In use, as a mower travels along, the blade assembly revolves, any long grass stalk encountered passes down a slot and into the aperture instead of being flattened by the rotation of the blade assembly as normally happens, so that instead of springing up after passage of the mower, the stalk is cut off at its base by the knife-like edge of the aperture that has entrapped it. The invention is applicable not only to motordriven mowers but also hand-propelled ones.

In order that the invention may be more clearly understood, reference will now be made to the accompanying drawings which schematically show one embodiment thereof by way of example and in which: Fig. 1 shows a single mower blade in the flat state before fitting, and Fig. 2 shows a perspective view of a fivebladed mower cutter assembly removed from a mower frame.

Referring now to the drawings, Figure 1 shows a single blade 1 drawn in the flat state before fitting to the mower, with a straight slot 2 leading from the edge into an oval-shaped aperture 3. Although the drawing shows apertures all along the blade they may be limited to the middle part of the blade.

The apertures may be spaced apart by about 21 inches to 3 inches.

Fig. 2 shows a mower cutter assembly comprising five such blades cylindrically arranged about and secured to a central shaft 4, each blade 1 having four of the apertures 2, 3 which are arranged in a helical path denoted by the arrowed dotted line.

This assembly is mounted in a conventional mower frame, so that the assembly co-operates with a stationary shear blade in the usual fashion. The frame and anvil or shear blade are thus conventional and have not been illustrated.

When the cutter assembly is applied to mowers of the type in which the front of the mower is supported on a transverse cylindrical idler roller in front of the cutter assembly, for example a roller mower as distinct from a side-wheel mower, the roller tends to flatten the long stalks so that some of them may not return to a sufficiently upright position before the are encountered by the cutter assembly, and may not be severed. In order to overcome this problem, the standard roller may be replaced by a pair of side wheels or the like (not shown) mounted interiorly or exteriorly of, and preferably directly adjacent, the side frame members of the mower, so as to eliminate, or substantially reduce, flattening of the grass in front of the cutter assembly. A similar result may be achieved by employing a series of axially spaced wheels or rollers, or a roller or roller assembly having a peripheral surface provided with a series of axially spaced lands or corrugations.

The apertures 3 are shown as being oval in shape but any re-entrant shape may be employed such as triangular or trapezium or dove-tailed: straight-sided shapes may be found to be easier to stamp out of the blade for manufacturing purposes. The edges of the entry slot 2 and the apertures 3 are preferably sharpened.

Furthermore, the amount of staggering between the apertures of adjacent blades as shown in Figure 2 may be modified so that the entrances to the apertures 3 may present, to the fixed anvil blade (not shown) either a continuous or an intermittent transverse sweep.

Where, as in the illustrated embodiment, the cutting action is produced by the interaction of a rotary blade (or blades) or equivalent with a relatively fixed member (or members) such as an anvil or shear or counter blade, one or more of the apertures may be provided in the edge of that member that co-operates with the rotary blade instead of, or in addition to, in the blade itself.

When the mower or other device is motor powered, at least the blade or blades or equivalent may be driven by an internal combustion engine, or a mains-or batteryoperated electric motor, associated with the device, or coupled thereto, for example by an appropriate power take-off.

WHAT I CLAIM IS: 1. A cylinder mower having a cutter assembly comprising a plurality of blades, wherein at least one of said blades is provided with at least one aperture of reentrant shape to entrap and cut off long grass stalks.

2. A mower as claimed in claim 1, wherein each blade is provided with a number of said apertures.

3. A mower as claimed in claim 2, wherein the apertures are staggered from blade to blade.

4. A mower as claimed in claim 3, wherein the apertures follow a helical path.

5. A mower as claimed in any one of the preceding claims, wherein the or each aperture comprises a straight-sided slot which opens out into a re-entrant shaped portion.

6. A mower as claimed in claim 5, wherein the edges of the or each aperture is sharpened.

7. A cylinder mower having a cutter assembly substantially as hereinbefore described with reference to Fig. 2 of the accompanying drawings.

8. A rotatable cutter assembly for a cylinder mower, comprising a plurality of blades formed with re-entrant apertures which open into the cutting edges of the blades.

9. A mower as claimed in any of claims 1 to 7, or a mower provided with a cutter assembly as claimed in claim 8, wherein a mower, forwardly of the cutter assembly, is supported by rolling means having circumferentially extending. axially spaced lands.

10. A mower as claimed in claim 9, wherein said rolling means comprise a pair of idler wheels spaced apart by a distance approaching, or greater than, the length of the blades in the direction of the rotational axis of the cutter assembly.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. cylindrical idler roller in front of the cutter assembly, for example a roller mower as distinct from a side-wheel mower, the roller tends to flatten the long stalks so that some of them may not return to a sufficiently upright position before the are encountered by the cutter assembly, and may not be severed. In order to overcome this problem, the standard roller may be replaced by a pair of side wheels or the like (not shown) mounted interiorly or exteriorly of, and preferably directly adjacent, the side frame members of the mower, so as to eliminate, or substantially reduce, flattening of the grass in front of the cutter assembly. A similar result may be achieved by employing a series of axially spaced wheels or rollers, or a roller or roller assembly having a peripheral surface provided with a series of axially spaced lands or corrugations. The apertures 3 are shown as being oval in shape but any re-entrant shape may be employed such as triangular or trapezium or dove-tailed: straight-sided shapes may be found to be easier to stamp out of the blade for manufacturing purposes. The edges of the entry slot 2 and the apertures 3 are preferably sharpened. Furthermore, the amount of staggering between the apertures of adjacent blades as shown in Figure 2 may be modified so that the entrances to the apertures 3 may present, to the fixed anvil blade (not shown) either a continuous or an intermittent transverse sweep. Where, as in the illustrated embodiment, the cutting action is produced by the interaction of a rotary blade (or blades) or equivalent with a relatively fixed member (or members) such as an anvil or shear or counter blade, one or more of the apertures may be provided in the edge of that member that co-operates with the rotary blade instead of, or in addition to, in the blade itself. When the mower or other device is motor powered, at least the blade or blades or equivalent may be driven by an internal combustion engine, or a mains-or batteryoperated electric motor, associated with the device, or coupled thereto, for example by an appropriate power take-off. WHAT I CLAIM IS:

1. A cylinder mower having a cutter assembly comprising a plurality of blades, wherein at least one of said blades is provided with at least one aperture of reentrant shape to entrap and cut off long grass stalks.

2. A mower as claimed in claim 1, wherein each blade is provided with a number of said apertures.

3. A mower as claimed in claim 2, wherein the apertures are staggered from blade to blade.

4. A mower as claimed in claim 3, wherein the apertures follow a helical path.

5. A mower as claimed in any one of the preceding claims, wherein the or each aperture comprises a straight-sided slot which opens out into a re-entrant shaped portion.

6. A mower as claimed in claim 5, wherein the edges of the or each aperture is sharpened.

7. A cylinder mower having a cutter assembly substantially as hereinbefore described with reference to Fig. 2 of the accompanying drawings.

8. A rotatable cutter assembly for a cylinder mower, comprising a plurality of blades formed with re-entrant apertures which open into the cutting edges of the blades.

9. A mower as claimed in any of claims 1 to 7, or a mower provided with a cutter assembly as claimed in claim 8, wherein a mower, forwardly of the cutter assembly, is supported by rolling means having circumferentially extending. axially spaced lands.

10. A mower as claimed in claim 9, wherein said rolling means comprise a pair of idler wheels spaced apart by a distance approaching, or greater than, the length of the blades in the direction of the rotational axis of the cutter assembly.