GB2252891A - A scarifier - Google Patents

Abstract

A scarifier blade for use in a rotary or hover mower comprises a generally planar steel strip (1) to which are attached, as by welding, a number of protrusions (5). In the preferred embodiment each protrusion (5) is in the form of a flat steel tooth of generally triangular shape with the base of each tooth welded to the strip (1). In use, the protrusions (5) catch in the thatch of a lawn thereby pulling the undesirable thatch upwards to be cut-off by the leading edge of the blade. <IMAGE>

Description

A SCARIFIER This invention relates to a scarifier, and more particularly to a scarifying blade for attachment to a conventional rotary or hover-mower.

Over a period of time a lawn will develop a thatch comprising the surface roots of the grass, moss, and trailing weeds and grasses. The development of this thatch is considerably exacerbated by the use of hover-mowers, and other grass cutting machines where the grass clippings are left to lie on the turf. If this thatch can be lifted and broken up, the quality of the turf will be greatly improved.

For many years the removal of the thatch was achieved in private gardens by the use of a hand held fan or lawn rake, though this was a strenuous job. Commercial scarifiers have been well-known for a number of years, these being machines which pull the thatch out from the grass, and which are adapted to operate on a large scale suitable for use on the grass of sports grounds, parks or the like. More recently, domestic, electric scarifiers have become available. These typically comprise a rotating cylinder from which protrude rows of sprung metal hooks. The hooks catch in the thatch as the scarifier is pushed forward over the lawn by means of a handle, and the thatch is thus lifted from the finer grasses.An alternative solution has been provided for the small domestic user in the shape of an attachment which can be fitted to the rear of a conventional cylinder lawnmower, such that as the lawnmower is pushed forward, the attachment catches into the thatch behind the lawnmower and lifts it away from the finer grass.

According to the present invention there is provided a scarifier blade adapted to be fitted to a rotary or hover-mower in place of the usual cutting blade, the scarifier blade comprising a generally planar strip rotatable about an axis perpendicular to the plane of the strip and a plurality of rigid protrusions extending downwardly from the plane of the strip when the blade is fitted to the mower.

Preferably the protrusions are equi-spaced on either side of the axis, and the protrusions are integrally formed with said blade.

In a particularly preferred embodiment of the invention the protrusions are flat teeth, preferably of generally triangular shape, with the base of each tooth secured to the strip so that an apex of each tooth is at the end of the tooth remote from the strip. The teeth and strip are preferably formed of steel plate and are secured together by welding.

In the preferred embodiment the blade is aerodynamically shaped to provide an air flow tending to blow the removed thatch into the grassbox of the mower to which it is attached.

An embodiment of the invention will now be described in more detail by way of example with reference to the accompanying drawings in which: Figure 1 shows a plan view of an embodiment of the scarifier blade according to the present invention; Figure 2 is an end view of the blade of Figure 1; and Figure 3 is a side view of the blade of Figure 1.

As shown in the drawings, the scarifier blade comprises a generally planar steel strip 1. The blade is adapted to be fitted to a conventional rotary hover-mower which normally operates with a substantially horizontal cutting blade rotating on a substantially vertical driving shaft. A hole 2, as shown in Figure 1 at the centre of blade 1, allows the blade of the invention to be fitted to the driving shaft in place of the usual cutting blade. The blade 1 is aerodynamically shaped with dropped front edges 3 and raised rear corners 4 to provide an air flow tending to blow the removed thatch into the grass box of the mower to which it is attached. A number of protrusions 5 extend from one planar surface of the blade, the protrusions being intended to extend downwardly when the blade is fitted to the hover-mower.Each protrusion 5 is in the form of a flat steel tooth of generally triangular shape with the base of each tooth welded to the strip 1. The protrusions 5 are intended to catch into the thatch of the lawn and as the blade 1 rotates on the vertical driving shaft of the mower the undesirable thatch is pulled upwards and is subsequently cut by the fast rotating leading edges of the blade. Thus the blade provides a scarifying action and a simultaneous cutting action for the grass. In the embodiment shown in the drawings the protrusions 5 have a front or leading edge 6 perpendicular to the plane of the blade and an angled rear or trailing edge 7 such that each protrusion tapers inwardly as it extends from the strip, Any other suitable form of protrusion or hook may be used.

As shown in Figure 1, the protrusions 5 are staggered along the blade alternately in front of and behind the longitudinal centre-line of the strip 1. Other configurations are, however, envisaged. The main requirement is that the balance of the blade is maintained by an equal distribution of weight on either side of the centrepoint through hole 2 about which the blade rotates.

Thus the configuration of the protrusions 5 is preferably arranged such that each protrusion is balanced by an equispaced protrusion on the other side of the hole 2.

Claims (5)

1. A scarifier blade adapted to be fitted to a rotary or hover-mower in place of the usual cutting blade, the scarifier blade comprising a generally planar strip rotatable about an axis perpendicular to the plane of the strip and a plurality of rigid protrusions extending downwardly from the plane of the strip when the blade is fitted to the mower.

2. A scarifier blade according to claim 1 wherein the protrusions are equi-spaced on either side of the axis and the protrusions are integrally formed with the blade.

3. A scarifier blade according to claim 1 or claim 2 wherein the protrusions are flat teeth, preferably of generally triangular shape, with the base of each tooth secured to the strip so that an apex of the tooth is at the end of the tooth remote from the strip.

4. A scarifier blade according to any preceding claim wherein the teeth and strip are formed of steel plate and are secured together by welding.

5. A scarifier blade substantially as hereinbefore described with reference to the accompanying drawings.