GB2118811A

GB2118811A - Lawn edge trimmer attachment

Info

Publication number: GB2118811A
Application number: GB08212364A
Authority: GB
Inventors: David Adams
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-04-28
Filing date: 1982-04-28
Publication date: 1983-11-09
Also published as: GB2118811B

Abstract

Attachment for fitting to a grass cutter comprises a housing 10 in which a blade carrier 20 is rotatably mounted, the blade carrier having means 12 for attachment to an external driveshaft and at least one cutter blade mounted thereon, the housing having a fixed cutter blade mounted thereon at the periphery of the circle described by the blade on rotation of the carrier, an aperture 14 being provided in the housing in the vicinity of the fixed blade allowing material to be trimmed to be presented to the cutting edges of the blades. The blades may be replaceable. <IMAGE>

Description

SPECIFICATION Lawn edge trimmer.atachment The present invention concerns a lawn edge trimmer attachment.

According to the present invention there is provided a lawn edge trimmer attachment comprising a housing in which a blade carrier is rotatably mounted, the blade carrier having means for attachment on an external driveshaft and at least one cutter blade mounted thereon, the housing having a fixed cutter blade mounted thereon at the periphery of the circle described by the blade on the blade carrier on rotation of said carrier, an aperture being provided in the housing in the vicinity of the fixed blade allowing material to be trimmed to be presented to the cutting edges of the blades.

Preferably the blade carrier is provided with four equi-spaced blades each extending substantially radially therefrom. Preferably said blades are replaceable and to facilitate replacement they have a bulbous protrusion at their inner end accommodated in a correspondingly shaped enlargement at the lower end of a slot in the blade carrier adapted to accommodate the blade.

Preferably the fixed blade mounted in the housing is adjustably fixed to a carrier which is movable relative to the housing to provide adjustment of said blade relative to the rotatable blade or blades. This fixed blade has a cutting edge which is inclined with respect to the axis of rotation of the moving blades.

Preferably, with the exception of the blades, the attachment is manufactured from plastics material.

The housing may have guide means thereon for adjusting the spacing between said opening for material to be trimmed and said guide means, the guide means being intended to rest against the edge of a lawn to be trimmed.

Preferably the attachment is adapted for mounting on a grass cutter of the type having a nylon cutting cord rotatably mounted remote from the drive means at the end of an arm, for example a Strimmer (Trade Mark of Black 8 Decker Limited). To facilitate this the housing is provided with a suitable clamp for attaching it to the end of the arm and the blade carrier drive receiving means is adapted to receive the end of the flexible driveshaft of the apparatus.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings irr which: Fig. 1 shows an elevation of a lawn edge trimmer attachment, Fig. 2 is partially section top plan view thereof, Fig. 3 is sectional view through a blade carrier of the attachment, and Fig. 4 an end view of a fixed blade of the attachment.

A lawn edge trimmer attachment is adapted for mounting on a grass cutter of the type comprising a power unit, for example an electric motor or internal combustion engine, arranged at one end of a hollow arm in which is mounted a flexible driveshaft, the other end of the arm normallrbeing provided with a bush form which projects one or more nylon cutting cords which, on being rotated at relatively high speed by the motor, are used to cut grass around trees, edges, etc. An arrangement of this type sold by Black 8 Decker Limited is known as a "Strimmer".

The attachment of the present invention is adapted for fitment to a grass cutter of this type in place of the bush carrying the nylon cutting cord or cords.

It comprises a housing 10 moulded from a plastics material having at one end thereof clamping means 12 to enable the housing to be attached to the lower end of the arm. The housing is provided with an opening 14 in one side and adjustable guide means (not shown) are attached to lugs 1 6 arranged on either side of the opening 14. The upper and lower ends of the casing are enclosed.

A blade carrier 20 which may also be manufactured from plastics material is rotatably mounted in the housing by means of a stub shaft 22 mounted in a bush or bearing 24 fixed in the lower end corner 1 8 of the housing 1 0. The end of the rotatable member 20 remote from the stub shaft 22 is provided with means for accepting the free end of the flexible driveshaft of the grass cutter. This may be a square hole or a hole incorporating keys or any other suitable means. It is illustrated diagrammatically in the drawings at 26.

Four steel blades 28 are replaceably mounted in the blade carrier 20 and, as can be seen from Fig. 3, this replaceable mounting may be provided by forming bulbous ends 30 on the blades and passages 32 of corresponding cross-section at the bottom of slots 34 formed in the blade carrier 20 for receiving the blades. The blades are all of the same length such that on rotation of the blade carrier they each define a common cutting circle.

The blades shown in the embodiment are straight for ease of manufacture and economy, but may have a helical form.

The rotatable blades 28 are adapted to co-act with a fixed blade 40 rigidly mounted on the housing 1 0. The blade 40 is carried by a blade carrying block 42 rigidly mounted on the housing and means may be incorporated in the mountings of the blade to the block and the block to the housing to provide for adjustment of the cutting edge of the blade 40 relative to the axis of rotation and hence the cutting circle of the rotatable blades 28. As can be observed from Fig. 4, the cutting edge of the fixed blade 40 is inclined.

In operation, the attachment is held against the edge of the lawn to be cut with the axis of the blade carrier approximately vertical the guide means hold it at a predetermined spacing from the edge. The blades 28 are rotated past the fixed blade 40 and any grass projecting into the aperture 14 in the housing is sheared off between the fixed and rotating blades. Thus, the edge, after the attachment has been passed over it, has a nearly trimmed appearance.

Additional means (not shown) may be provided in the housing so that cut grass blades may be discharged therefrom.

Various modifications can be made without departing from the scope of the invention; for example it may be found that less than 4 rotatable blades are required. As indicated above the rotatable blades may be straight or curved and the means for mounting them to the blade carrier can be modified in any suitable manner. Additionally the means for fixing the attachment to the end of the arm of the grass cutter may be modified to suit the particular cutter concerned. The blades may for example be rivetted to the blade carrier instead of being replaceable therein, the whole blade carrier plus blades being replaced when necessary.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to whether or not particular emphasis has been placed thereon.

Claims

1. A lawn edge trimmer attachment comprising a housing in which a blade carrier is rotatably mounted, the blade carrier having means for attachment to an external driveshaft and at least one cutter blade mounted thereon, the housing having a fixed cutter blade mounted thereon at the periphery of the circle described by the blade on the blade carrier on rotation of said carrier, an aperture being provided in the housing in the vicinity of the fixed blade allowing material to be trimmed to be presented to the cutting edges of the blades.

2. A lawn edge trimmer attachment as claimed in claim 1 in which the blade carrier is provided with four equi-spaced blades each extending substantially radially therefrom.

3. A lawn edge trimmer attachment as claimed in claim 1 or claim 2 in which said blades are removably replaceable and to facilitate replacement they have a bulbous protrusion at their inner end accommodated in a correspondingly shaped enlargement at the lower end of a slot in the blade carrier adapted to accommodate the blade.

4. A lawn edge trimmer attachment as claimed in any preceding claim in which the fixed blade mounted in the housing is adjustably fixed to a carrier which is movable relative to the housing to provide adjustment of said blade relative to the rotatable blade or blades.

5. A lawn edge trimmer attachment as claimed in any preceding claim in which the fixed blade has a cutting edge which is inclined with respect to the axis of rotation of the moving blades.

6. A lawn edge trimmer attachment as claimed in any preceding claim in which, with the exception of the blades, the attachment is manufactured from plastics material.

7. A lawn edge trimmer attachment as claimed in any preceding claim in which the housing has guide means thereon for adjusting the spacing between said opening for material. to be trimmed and said guide means, the guide means being intended, in use, to rest against the edge of a- lawn to be trimmed.

8. A lawn edge trimmer attachment as claimed in any preceding claim adapted for mounting on å grassvcutter of the type having a nylon cutting cord rotatably mounted remote from the drive means et the end of an arm.

9. A lawn edge trimmer attachment as claimed in claim 8 in which the housing is provided with a suitable clamp for attaching it to the end of the arm and the blade carrier drive receiving means is adapted to receive the end of the flexible driveshaft of the apparatus.

10. A lawn edge trimmer attachment as claimed in any preceding claim in which the housing is provided with means allowing cut grass blades to be collected therefrom..

11. A lawn edge trimmer attachment as claimed in claim 10 in which said means allowing cut grass blades to be discharged therefrom includes a means for collecting the cut grass.

12. A lawn edge trimmer attachment substantially as hereinbefore described with reference to the accompanying drawings.