GB2285380A - Lawn trimmer - Google Patents

Description

1 Lawn trimmer

Background art

2285380 The invention proceeds from a lawn trimmer of the type defined in the preamble of claim 1.

Such lawn trimmers are suitable for flat trimming and perpendicular or vertical trimming, the latter being used, for example, for edge cutting. For vertical trimming, the lawn trimmer is to be placed onto the guide, which conveys the lawn trimmer at the correct distance from the ground in order to achieve optimum cutting efficiency.

In known lawn trimmers of said type, the guide takes the form of a roller, which is held about an axis of rotation, which extends parallel to the trimmer axis, laterally of the protective hood, and indeed centrally in relation to the release opening for the trimming fibre in the protective hood. The rotatable roller, whose radius is dimensioned according to the optimum cutting distance, allows efficient operation during vertical trimming but, because of its size, considerably impairs visibility during flat trimming.

Advantages of the invention In contrast, the lawn trimmer according to the invention having the characterizing features of claim 1 has the advantage that the wire hoop, which may be moved into a used or operating position and into a non-used or pause position, during vertical trimming allows optimum sliding of the trimmer along garden paths and lawn edges and by presetting the 2 correct distance protects the trimming fibre from excessive wear, and during flAt trimming, after the wire hoop has been pushed manually into its pause position, lies against the protective hood and does not conceal or otherwise impede the field of action of the trimming fibre. The spring properties of the wire hoop and the protective hood, which is generally made of plastic, are utilized in such a way that the wire hoop is seated without play in its catches.

By virtue of the measures outlined in the further claims, advantageous developments and improvements of the lawn trimmer indicated in claim 1 are possible.

Drawings The invention is explained in greater detail in the following description of an embodiment which is illustrated in the drawings. The drawings show:

Fig. 1 Fig. 2 Fig. 3 Fig. 4 in a cutout manner, a perspective view of a lawn trimmer during flat or horizontal trimming, in a cutout manner, a perspective view of the lawn trimmer of Fig.1 during perpendicular or vertical trimming, a plan view of a wire hoop used as a vertical trimming guide on the lawn trimmer according to Figs.1 and 2, an enlarged view of a cutout of the lawn trimmer of Figs.1 and 2, partially in section.

3 Description of the embodiment

The lawn trimmer, which is shown in a cutout manner in Figs.1 and 2 in two positions for different trimming tasks, comprises a trimming fibre 11 which is wound up in a fibre drum 10 and is withdrawn from said drum by a specific length, the trimming fibre via the fibre drum 10 being set in rotation by an electric motor and generating an annular rotational path. Only the motor housing 12 of the electric motor is shown in Figs.1 and 2. The rotational path of the trimming fibre 11 is partially covered by a protective hood 13, the protective hood 13 at its side remote from the user exposing the rotational path of the trimming fibre 11 in the region of the latter's field of action. As a whole, the protective hood 13 is sector-like in appearance, having two diametrically opposed convex contours 131 and 132, the curved contour 131 with a much greater radius extending over an angle at circumference of around 1800. For operation, the lawn trimmer is guided by means of a handlebar 14.

During flat trimming, the lawn trimmer is guided with the bottom edge 133 of the protective hood 13 on the surface of the lawn. The position of the lawn trimmer in such a case is shown in Fig.l. The lawn surface is indicated by 15. For perpendicular or vertical trimming, e.g. for cutting the edges of a lawn, the lawn trimmer has a vertical trimming guide 16, which is realized by a wire hoop 17 which may be pulled radially outwards from the protective hood 13.

The wire hoop 17 is shown in Fig.3 in plan view and in Fig.4 in side view. It is substantially U-shaped, having a curved hoop web 20 from which two hoop limbs 21, 22 project approximately at right angles. The hoop limbs 21, 22 are, approximately in the middle, bent at right angles in such a way that each hoop limb 21 or 22 is subdivided into three limb portions. The two end limb portions 211, 221 are offset towards one another into the hoop interior relative to the 4 web-side limb portions 212, 222 and extend substantially parallel to the web-side limb portions 212, 222, by which is also understood a slight bias with the advantage of improved bracing. Said bending at right angles produces, in each hoop limb 21, 22, a middle limb portion 213 or 223 which extends at right angles to the other two limb portions 211, 212 and 221, 222. Formed at each of the ends of the hoop limbs 21, 22 is a stop 23 or 24. When the wire hoop 17 is fitted in the protective hood 13 (Fig. 5), said two stops 23, 24 lie on the underside of the wire hoop 17.

As Fig.5 shows, the wire hoop 17 is accommodated in an axially displaceable manner with its end limb portions 211, 221 in two guide shafts which are formed in the protective hood 13. In Fig.5, only the right guide shaft 25 may be seen. Disposed at the - in withdrawal direction - front edge of the guide shafts 25 are counterstops, which cooperate with the stops 23, 24 on the wire hoop 17 and prevent the wire hoop 17 from being pulled out of the guide shafts 25. In Fig.5, again only the counterstop 26 in the right guide shaft 25 is visible. An identical counterstop is also provided in the left guide shaft not shown here.

The wire hoop 17 is latchable on the protective hood 13 by being pulled out or pushed into two positions. In the nonused or pause position of the wire hoop 17, which is shown in Fig.1 and is manually produced when flat trimming, the curved hoop web 20 of the wire hoop 17 lies directly against the protective hood 13 and extends along the curved contour 132 of the protective hood 13, either flush with the protective hood edge or at a slight radial distance from the protective hood edge. In the used or operating position of the wire hoop 17, as shown in Fig.2, the curved hoop web 20 of the wire hoop 17 is displaced outwards by a defined radial distance. Said radial distance is so selected that, when the lawn trimmer is placed onto the hoop web 20 of the wire hoop 17 (Fig.2), the trimming fibre 11 achieves an optimum cutting efficiency. For latching of the wire hoop 17 on the protective hood 13, two detent hook pairs - one in withdrawal direction and one in insertion direction of the wire hoop 17 are disposed at a distance one behind the other on the top of the protective hood 13. The detent hooks of the - in withdrawal direction front detent hook pair are designated 31 and 32 and the detent hooks of the - in withdrawal direction - rear detent hook pair are designated 33 and 34. The left detent hooks 31 and 33 of the two detent hook pairs are shown in Figs.1 and 2 and the right detent hooks 32, 34 of the detent hook pairs are shown in Fig.S. The successively arranged detent hooks 31, 33 and 32, 34 are aligned with one another in the withdrawal and insertion direction of the wire hoop 17 and are disposed in the path of displacement of the middle limb portions 213, 223 of the hoop limbs 21, 22, with the result that said middle limb portions 213, 223 form detent pins 27, 28 which cooperate with the detent hooks 31 - 34. As is shown in Fig.5 for the detent hooks 32 and 34, all of the detent hooks 31 - 34 have a detent trough 35, which is open towards the withdrawal direction of the wire hoop 17 for receiving one of the two detent pins 27, 28 of the wire hoop 17, and a detent lug 36 which engages over the received detent pin 27, 28.

In Fig.5, the wire hoop 17 is shown in its maximum withdrawal position, in which the stops 23, 24 on the wire hoop 17 strike against the counterstops 26 in the guide shafts 25 and prevent further movement of the wire hoop 17. By pushing the wire hoop 17 back in the direction of arrow 29 in Fig.5, the wire hoop 17 with the detent pins 27, 28 (of which only the detent pin 28 is shown in Fig.5) latches into the detent hooks 31 and 32 of the front detent hook pair (of which only the detent hook 32 is shown in Fig.5). Said latched position corresponds to the operating position of the wire hoop 17 for vertical trimming. The manner of holding the lawn trimmer during vertical trimming is shown in Fig.2, which clearly reveals how the wire hoop 17 is placed with its hoop web 20 onto the lawn 6 surface, which is again indicated by 15. In said position, the lawn edge 18 may be vertically trimmed.

For flat trimming (Fig.1), the wire hoop 20 is pushed back fully against the protective hood 13. For said purpose, it is first withdrawn manually in the direction of arrow 30 in Fig.5 out of the detent hooks 31, 32 of the front detent hook pair, then raised and pushed back once more in the direction of arrow 29 past the detent hooks 31, 32 until the two detent pins 27, 28 latch into the detent hooks 33, 34 of the rear detent hook pair. To said end, the guide shafts 25 are so dimensioned that, when the wire hoop 17 is raised in order to lift it past the front detent hooks 31, 32, the limb ends of the wire hoop 17 may swivel accordingly in the guide shafts 25.

In an embodiment of the invention which is not illustrated, the wire hoop 17 carries a push-on plastic part which serves as a handle for adjusting the wire hoop 17.

7

Claims (1)

1. Claims

   Lawn trimmer, having a protective hood (13) which partially covers the rotational path of a rotating trimming fibre (11), and having a guide (16) projecting laterally from the protective hood (13) for perpendicular or vertical trimming, characterized in that the vertical trimming guide (16) is formed by the hoop web (20) of a wire hoop (17), whose hoop limbs (21, 22) are latchable on the protective hood (13) in a used and a non- used position of the vertical trimming guide (16) in such a way that the hoop web (20) in the non-used position extends substantially along a protective hood edge portion, either flush with or at a slight radial distance from said protective hood edge portion, and in the used position is displaced outwards by a defined radial distance relative to said protective hood edge portion.

   2. Lawn trimmer according to claim 1, characterized in that the wire hoop (17) is substantially U-shaped with a curved hoop web (20) and two limbs (21, 22), which extend parallel to one another and approximately in the middle are bent at right angles in such a way that the end limb portions (211, 221) extend substantially parallel to and are offset in towards one another relative to the webside limb portions (212, 222), and that a middle limb portion (213 or 223) extending between and at right angles to the two limb portions (211, 212 and 221, 222) of each limb (21 and 22) forms a detent pin (27 and 28) for latching of the wire hoop (17) in the used and nonused position of the vertical trimming guide (16).

   8 3.

   Lawn trimmer according to claim 2, characterized in.that on the top of the protective hood (13) two detent hook pairs (31, 32 and 33, 34) are disposed at a distance one behind the other in withdrawal and insertion direction of the wire hoop (17) and that each detent hook (31-34) has a detent trough (35), which is open towards the withdrawal direction of the wire hoop (17) for receiving one of the two detent pins (27, 28) on the wire hoop (17), and a detent lug (36) which engages over the detent pin (27 or 28).

   4. Lawn trimmer according to claim 2 or 3, characterized in that disposed in the protective hood (13) behind the - in the withdrawal direction of the wire hoop (17) - rear detent hook pair (33, 34) are guide shafts (25) for receiving the end limb portions (211, 221) of the wire hoop (17).

   Lawn trimmer according to claim 4, characterized in that formed on each limb end of the wire hoop (17) is a stop (23, 24) which cooperates with a counterstop (26) in the guide shaft (25) to limit the withdrawal of the wire hoop (17).

   6. Lawn trimmer according to claim 5, characterized in that the stops (23, 24) and counterstops (26) are disposed in such a way as to prevent an escape of the limb ends of the wire hoop (17) from the guide shafts (25).

   Lawn trimmer according to one of claims 4 - 6, characterized in that the height of the guide shafts (25) for the end limb portions (211, 221) of the wire hoop (17) is so dimensioned that the limb ends may execute the necessary swivelling movement in the guide shafts (25) to lift the detent pins (27, 28) on the wire hoop (17) past the - in withdrawal direction of the wire hoop (17) front detent hooks (31, 32).

   9 8. Lawn trimmer according to one of claims 1 to 7, characterized in that the wire hoop (17) is surrounded by, in particular extrusion-coated with, plastics material.

   9. A lawn trimmer substantially as herein described with reference to the accompanying drawings.