DE102009058396A1 - Lawn edge cutter for cutting grass edges and overgrowths at pathways and curb stones, has frame with impellers, cutter in vertical cutting plane and motor for drive of cutter, where cutting plane is extended along lawn edge - Google Patents

Abstract

The lawn edge cutter has a frame with impellers, a cutter in vertical cutting plane and a motor for a drive of the cutter, where the cutting plane is extended along a lawn edge. A blunt cutter performs a small horizontal stroke with high frequency. The position of the cutter is guided by the impellers on the frame for lawn upper surface for the purpose of adherence of a defined penetration depth in the lawn.

Description

In the garden there are lawn edges at transitions to pavement slabs, end plates, beds, vertical finishes such. B. walls.

When mowing the upstanding stalks of the lawn are always cut. It can expand parallel to the ground, overgrowing the edges of paving slabs, growing into the joints between the slabs, or growing into beds bordering the lawn. If the lawn is limited by vertical surfaces, mowing the lawn will not mow a strip of a few centimeters along that wall.

For trimming the unmown strip along vertical boundaries, lawn edge shears are known which are either hand operated or motor driven. The writing movement can also be generated automatically by a driving movement, as in DE 20 58 984 and DE 19 13 299 made known. The scissors can consist of one or more upper and lower knife pairs.

In addition, lawn edge cutter are known, which are equipped instead of the scissors with a circumferentially driven cutting line.

These types of lawn edge trimmers are very limited in the applications, namely only as a supplement to the lawnmower in the edge strip z. B. along a wall where the lawnmower does not go.

The easiest way to achieve a clean transition is to use a slightly modified spade in the turf / plate and turf bedding transitions, where the turf edges are formed by perpendicularly grooving the spade. In the case of lawns growing over paving slabs, the problem arises of always hitting the very edge of the slab, which one can not see. That is why at such lawn transitions often worked with a knife and the grass overhang cut off, so to speak. This manual method is physically exhausting and tedious.

DE 20 2004 020 170 U1 shows a proposal where an inserted between turf and plates obliquely hired knife attached to a chassis is pushed forward intermittently while exerting separation effect. The problem is that the grass dodges laterally in front of the cutting edge and is not cut clean.

According to DE 20 2008 017 462 U1 a cutting edge can be moved vertically up and down by motor. The vertical stroke of the knife results in a continuous relatively large force in the feed direction. At the same time, there are also vertical forces trying to lift the device. By way of illustration, one can imagine a jigsaw that constantly requires high feed force and tends to jump through the reciprocal vertical cutting forces. In order to limit this jumping, it is ensured that the saw is pulled with its support surface against the cutting material during the forward stroke of the saw blade.

Accordingly, the direction of the toothing on the saw blade is designed. This defusing of the problem is not possible with a smooth knife of the proposal mentioned. A pendulum stroke only slightly mitigates the problem.

In the proposal, the blade movement creates a vibrating vertical force that the device wishes to lift, which is exacerbated when the blade is tilted.

The cutting movement of the knife, in particular the upward movement brings the upper layers of the overgrowing grass in particular individual blades of grass to avoid, so that no clean cut can be made.

In a large number of proposals, a rotating knife with a vertical cutting plane is immersed in the turf next to the edge of a plate. The rotary movement is driven by the travel movement along the edge of the plate. The force attainable by the contact friction of the wheels to the ground is much too small to drive the blade against the cutting force when cutting off a real grass overhang rather than just protruding blades of grass.

The knife can be designed as a circular knife as it EP 2022321 A1 represents.

It is now close to reducing the physical stress and overcoming the cutting forces to drive the rotational movement of the rotary blade independently by a motor. This is shown in the proposal EP 1616473 A1 , The circular blade is replaced by a knife with 2 circumferentially distributed cutting fingers with approximately radially extending cutting edge.

A major problem with these solutions is that the rotating cutting fingers can strike the plates of the walkway or end plates, thereby damaging themselves and the plates.

To DE 298 14 169 an attempt is made to avoid this problem. Through a leadership role, however, only against transverse to the direction of movement running edges on which the cutter is moved directly, butt and keep the rotating blade away.

The circulating motor-driven circular knives or flywheel also pose a great risk of injury. So that the lawn does not evade the rotating blades, the speed must be very high as a lawn mower, which increases the risk of damage and accidents. The circular knife can only work with a sharp edge. This brings an additional risk of injury even when the drive is stopped. The circular blade blunts through the circumferential movement and must be reground.

The object of the present invention is to provide a lawn edge cutter which avoids the mentioned problems and is to be used for all occurring transitions of the lawn.

For comfortable work, the device is motor-driven and mobile wheels on the lawn or the sidewalk plates.

Instead of the dangerous woodcut of the rotating beater blade and the equally dangerous and wear-prone drawing cut of the circular blade is cut by a vibration cut or pulse cut with horizontally lying amplitude. The knife, which works in a vertical Schreiebene along the lawn edge, dives by a certain amount t in the lawn. His cutting edge is arranged at an angle α of preferably 45 ° in the transport movement direction from top to bottom falling back.

The blade is deliberately dulled and presents no risk of injury.

A blunt edge can no longer become dull. There are no life problems with the knife.

The knife is attached to a mechanism that gives the knife a predominantly horizontal oscillatory movement of preferably 15 mm stroke at a frequency of preferably 25 Hz.

With each swing stroke, the blade cuts on the stroke in the feed direction by a small amount to a certain depth of penetration into the lawn. The cutting force goes against the direction of movement.

The cutting force pulses are only short and the inertial mass of the entire device prevents noticeable reactions, so that the operator can push continuously without great resistance through the cut the lawn edge cutter along the lawn edge. During the return stroke of the knife, one piece can be pushed on each. It can in this way at 10 mm effective feed / revolution of the driving motor and 25 strokes / second max. 15 m lawn edge to be cut in the minute.

The function of the pulse cut is to be understood as the function of a percussion drill or a pneumatic hammer, which can also be used with less force and with blunt tools. There is an analogy here with the cutting pulses and the blunt cutting edges.

The impulse cut allows the blade of the knife to be completely blunt.

The blunt cutting edge in conjunction with the small stroke completely eliminates the risk of injury. It is possible to put the hand on the knife in the barrel without the slightest injury occurring. The blunt knife will not be damaged if touched by stone edges and will not damage it. The life of the knife is extremely large.

So that the lawn is not laterally bent away in the direction of movement by the horizontal component of the cutting force, a hold-down roller is placed directly above the entry point of the knife into the lawn or advantageously slightly offset by the dimension x in the direction of travel, directly to the right and left of the cutting edge holds against the cutting force. The gap between the hold-down rollers also serves as orientation when driving the device along the lawn edge. Without the hold-down roll, the lawn will dodge before the blunt knife edge.

The hold-down rollers can also take over the impeller function at the same time.

When cutting the lawn edge running along pavement slabs or curbs, the device can be moved in both directions. The wheels of the device can run on the lawn or on the plates. For this purpose, however, the knife must be equipped with a backward cutting edge arranged in mirror image in addition to the cutting edge for forward operation.

The knife is interchangeable. To cut a lawn edge along a bed, a blade similar to a ploughshare is used, throwing the cut lawn aside where it can be raked off. Here, backward movement is not possible. The lawn edge at the transition lawn / Beeet can also be cut with the flat standard knife. The disposal of the section is then only slightly uncomfortable For the trimming of lawn edges along a vertical boundary z. B. Wall a knife is used with an oblique narrow fold on the blade trailing edge. It cuts at a distance of preferably 2 cm next to the vertical boundary (lawn edge stone, fence, wall) a few inches deep into the lawn and promotes using the fold at the trailing edge of the knife up the cut lawn and thereby cuts a virtually narrow groove. Here, too, you can cut with the standard knife instead of the special knife. The disposal of the lawn edge section is then only a little more expensive.

The power requirement of the blade drive is low because of the pulse cut: on the order of 200 W. Therefore, an electric motor is suitable for mains or battery power. The low power consumption is certainly a positive environmental factor.

For example, the movement of the knife is generated directly by the motor via an eccentric. Also conceivable is a magnetic oscillating drive.

Preferably, the chassis has 4 Wheels including the hold-down roller, which also acts as an impeller. Also advantageous is an arrangement of 3 Wheels including holding-down roller. The hold-down roller represents the front wheel. Behind the knife in the feed direction can 2 Impellers are arranged coaxially spaced from each other. They provide stability and prevent lateral tilting, provide a controlled penetration depth and allow the pivoting about the rear axis to disengage the knife and thus give the same features as in the arrangement with 4 Wheels. With only two wheels including hold-down roller, with the second impeller mounted behind the knife in the direction of travel, the stability is lost and the operator must always hold the device

The following is an exemplary embodiment of the device with reference to the drawings 1 to 8th described.

1 Lawn edge trimmer side view

2 Lawn edge cutter top view

3 Function lawn edge trimmer at transition lawns / paving slabs

4 Function lawn edge cutter at transition turf / curbs

5 Lawn edge trimmer for transition lawn / bed

6 Knife with ploughshare top view

7 Knife with ploughshare function

8th Lawn edge trimmer at transition lawn / wall

9 Function of the knife at transition lawn / wall

1 and 2 show the structure of the lawn edge cutter.

The frame consists of the front panel 1 , the rear flap 2 and the connection plate 3 ,

On the frame are preferably four wheels 4a ... d and the hold-down roll 5 with the same diameter as the wheels 4 , In another embodiment possibility, the impeller 4d omitted. On the frame is also stored the drive motor 6 , It can be a three-phase motor, AC motor or DC motor.

He drives over the eccentric pin 7 the lever 8th with the eccentricity e, thereby generating at the lever 8th with a ratio of the lever lengths b / a a mainly horizontal stroke of, for example, 15 mm on the knife. The lever 8th gets through the paddock 9 guided. In the simple mechanism proposed as an example, a small vertical stroke is generated on the knife, but it is harmless and taken in favor of a simple construction in purchasing. The knife does not move linearly but in a flat ellipse E whose large diameter is the stroke h.

The cutting edge of the knife 10a is directed by the angle α of preferably 45 ° to the turf surface. She dives into the lawn according to the measure t1. The knife cuts in the stroke forward in the feed direction by the stroke h in the lawn now. During the return stroke, the knife is then released and allows a powerless forwarding of the entire unit according to the movement v. The only short power pulses of the cutting are compensated by the inertial mass of the caddy and the engine, thereby avoiding jumping of the lawn edge cutter when cutting. The short-term torques on the motor for the generation of the current cutting force are compensated from the kinetic energy of the motor armature, so that a motor of about 200 W power is sufficient.

The advancement takes place manually over the arm 11 with the handle 11b in the thimble 11a on the arm 11 is slidably mounted and locked. For changing the direction of travel, the handle 1lb in the sleeve 11a be moved so that he is in position 11c stands. It is also ergonomically comfortable, the facility on the wheels 4b and 4c so swing that knife 10 austaucht. On the two wheels 4b and 4c The lawn edge trimmer can be moved to another location continuously. To park the lawn edge cutter, the handle can be used to save space 11b from the sleeve 11a be pulled out. Another possible way of doing this is that the handle 11b at the upper point of the arm 11 is mounted on a pivot point and can also be locked.

It can then be swiveled through 180 °.

The hold-down roll 5 is together with the impeller 4a , which has the same diameter, mounted on the frame so that the point of contact with the ground by the dimension x in front of the point of entry of the blade of the knife 10 is located in the ground. The lawn in front of the knife is thereby held and can not escape the knife in the direction of movement.

The knife 10 is about a known bayonet quick release on the lever, not shown 8th attached and can be easily replaced with other knives.

Special blades are provided for the different turf transitions.

3 shows the mode of action of the knife 10 at the transition lawn / sidewalk plates. The knife 10 cuts between the hold-down roller 5 and the impeller 4 in the lawn R close to the paving slab G and penetrates the measure t1 into the ground. The protruding part of the lawn RA is cut off. The frame with the wheels is located on the sidewalk plates. However, the lawn edge trimmer can also be located above the lawn, as is the case for the transition between lawn R and edge stones K 4 is shown.

The knife 10 for cutting the lawn edge on horizontal boundaries such as pavement slabs is formed flat as in 1 shown. The cutting edge 10a has bilateral flat bevel and forms a wedge whose tip is defused by rounding. By tempering or hardening, the knife has good wear properties.

To prune the lawn edge with transition to beds the same knife 10 used, but only simply cut into the lawn and the section must be removed manually.

By replacing the knife 12 with the cutting edge 12a and the fold 12b according to 5 and 6 in that the shape has a ploughshare, the cut grass RA can be thrown toward the bed B as in 7 shown.

The penetration depth t2 of the ploughshare blade 12 is preferably greater than the penetration depth t1 of the flat standard blade 10 ,

The raised truncated lawn RA can then be easily manually raked off after pruning the lawn edge.

To achieve a clean lawn edge adjacent to vertical boundaries such as wall, vertical lawn edging stones or fence can be a special knife 13 with the cutting edge 13a and the narrow fold 13b be used. It's at the lever 8th attached, so that the cutting plane turn between the impeller 4a and the hold-down roller 5 lies.

The knife penetrates by the measure t3, which is preferably smaller than the dimension t1 of the standard knife, in the ground. By the fold 13b it is kept away from the vertical boundary surface W by the dimension d. The fold is designed at a shallow angle β to the horizontal and promotes the lawn movement section during the driving movement of the lawn edge cutter. In this case, a groove of width d and depth t3 is cut into the lawn R. Please refer 8th and 9 ,

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 2058984 [0003]
• DE 1913299 [0003]
• DE 202004020170 U1 [0007]
• DE 202008017462 U1 [0008]
• EP 2022321 A1 [0013]
• EP 1616473 A1 [0014]
• DE 29814169 [0016]

Claims (11)

Lawn edge trimmer for trimming lawn edges and overgrowths on slab paths, curbs, vertical out of the grass level protruding boundaries such as lawn edging stones and walls, as well as at the transition to beds consisting of a chassis with wheels, a cutting knife in vertical, running along the lawn edge cutting plane and a motor for the drive of the knife, characterized in that a blunt knife with high frequency performs a small horizontal stroke h and thereby cuts the lawn with short cutting pulses, the cutting pulses always arise during the forward stroke and generate horizontal cutting forces, while in the backward movement, the knife free again is to allow a low-force Nachschieben the lawn edge cutter to the extent of the horizontal Schneidhubes along the lawn edge and that at least 2 wheels on the chassis, the position of the blade to the lawn surface for the purpose Einh tion of a defined depth of penetration into the lawn is forcibly guided. Lawn edge cutter according to claim 1, characterized in that the lifting movement is effected by a motor with preferably 1500 / min driven eccentric, in cooperation with a handlebar 9 a swinging motion on a lever 8th generates, which at the end of the lever 8th attached knife performs a mainly horizontal movement h. Lawn edge cutter according to claim 1, characterized in that the cutting edge of the knife at preferably 45 ° to the horizontal, falling back in the direction of travel from top to bottom, that its lower corner penetrates by a certain amount t in the ground, and that the cutting edge of the The knife is symmetrically wedge-shaped and blunted by rounding the tip to prevent injury and damage Lawn edge cutter according to claim 1, characterized in that above the penetration point of the cutting edge in the ground by the dimension x in the feed direction Niederhalterollen be directly left and right of the knife, which hold the lawn against the cutting force and prevent the dodge while cutting and at the same time also impeller function take. Lawn edge cutter according to claim 1 and 3, characterized in that there are respectively adapted blades for the different lawn edge transitions: lawn / horizontal boundary (plates, curbs), lawn / bed and lawn / vertical towering boundary (wall, lawn edging stones) and that the blades by a Quick release quick replaceable to adapt to the type of lawn edge. Lawn edge cutter according to claim 1, 3 and 5, characterized in that for the transition turf / plates a plane knife is used, which is designed to be short horizontally in the direction of travel to better follow the curves can. Lawn edge trimmer according to claim 1, 3 and 5, characterized in that the blade for the transition lawn / bed has a greater penetration depth and seen at the rear end in the direction of travel has an obliquely from bottom to top extending bevel at preferably 45 °, which has the shape of a ploughshare and heaps the cut lawn while driving along the bed Lawn edge cutter according to claim 1, 3 and 5, characterized in that the blade for the Rasenkantenbeschnitt with low penetration depth into the ground along a vertical surface, such. B. a wall, seen at the rear end in the direction of travel has a narrow right-angled fold which increases towards the direction of travel from bottom to top at a shallow angle of preferably 30 ° and conveys the lawn edge portion upwards and keeps the blade at a distance from the vertical boundary surface, wherein a groove is cut into the ground, the depth of the penetration depth of the blade and the width of the size of the fold corresponds. Lawn edge cutter according to claim 1, characterized in that the horizontal lifting movement is generated by a vibrating magnet. Lawn edge cutter according to claim 1, characterized in that the driving of the device along the lawn edge in both directions is possible, and that for the knife has a second of the first cutting mirror image opposite rear edge and that another hold-down roller above the penetration of the rear edge to the Dimension x offset in the feed direction is mounted. Lawn edge cutter according to claim 1, characterized in that the drive for the pulse cut by an electric motor of only about 200 W takes place, where it can be AC power from the mains or DC from a battery

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