WO1989005715A1

WO1989005715A1 - Attachment for hand-operated power-driven chain saws

Info

Publication number: WO1989005715A1
Application number: PCT/EP1988/001135
Authority: WO
Inventors: Johannes Möhlenkamp
Original assignee: Moehlenkamp Johannes
Priority date: 1987-12-14
Filing date: 1988-12-10
Publication date: 1989-06-29
Also published as: AU2903189A; DE8806704U1

Abstract

An attachment makes it possible to convert a hand-operated power-driven chain saw into a free cutter or similar. The attachment comprises a flat fastening element which can be fastened to the chain saw and can replace the guide bar. An elongated force-transmitting device extending from the front of the chain saw is connected at one end to the fastening element and to the toothed wheel of the chain saw by a chain and a second toothed wheel, and carries a free-cutting head or similar at the other end.

Description

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ATTACHMENT TO CONVERT A HΔND-ACTIVATED MQTOR CHAIN ΔGΞ

B e s c h r e i b u n

The invention relates to an attachment for converting a hand-operated chain saw into a brush cutter or the like.

Motor chain saws are used as mobile, portable devices in forestry and agriculture, for example for delimbing felled tree trunks and standing trees. Such chainsaws are however limited in their applicability. They are not very suitable for cutting bushes close to the ground or cutting branches higher on the tree. In addition, the conventional chain saws pose a considerable risk of injury to the user, since they have a saw chain with cutting teeth that revolves freely over most of the saw blade and on which the user can injure himself, particularly in the arm and hand area.

The measures developed by the inventor of the present application in accordance with European patent specification 0 070 361 and German utility model G 86 24 827 have considerably reduced the risk of injury in the case of hand-operated chainsaws; however, the variety of applications for chainsaws remains to be improved.

In the area of hand-operated, motor-driven cutting tools, there is in addition to the motor chain saw still the so-called brush cutter. This is used especially in forest culture maintenance. Such a brush cutter consists of a motor unit, the motor shaft of which is guided to a circular saw blade by means of a coaxial extension. The circular saw blade is provided with a known cover which can be pivoted in the circumferential direction. These brush cutters are used in particular to cut off bushes and ridges so that the forest plants are free and can unfold undisturbed. In addition, the brush cutter is used for refining, ie for removing weaker unwanted forest plants from the stock.

Known brush cutters, however, suffer from the occurrence of the so-called "kick-back" effect: when the rapidly rotating saw blade is attached to the drive or branch to be cut off, the device jumps away, to which the large lever between the hand-held motor and the distant saw blade contributes considerably . The use of such brush cutters is therefore still very limited. Especially in the upper performance class from 3 HP, which is particularly important for forestry and agricultural applications, there has been no satisfactorily working and in particular "kick-back" free device. Such brush cutters are much more suitable when equipped with thread heads for cutting green plants, grass and the like, in particular in the hobby area. Furthermore, from the point of view of the outlay, it is disadvantageous to have to purchase a brush cutter in addition to a motor chain saw in the forestry and agricultural sector and to take it to the place of use.

For individual motor chainsaws that are commercially available, an attachment has therefore been developed with which they can be converted into a brush cutter. To do this, the chain sword, the chain and the sprocket of the motor chain saw are removed; the motor shaft is coaxially coupled with a drive shaft extending laterally from the chain saw drive unit and running in a tubular casing. At the free end of the drive shaft there is a conventional clearing head with a cover which can be pivoted away in the circumferential direction of the circular saw blade. An example of this is the header according to DE-OS 16 28 906.

However, the chain saw converted to a brush cutter does not yet meet the requirements. The direct connection of the motor shaft and the drive shaft limits the usability of the attachment to motor chain saws with a specific, suitable motor shaft. The handles and emergency shutdown devices of the motor chain saw cannot be used, since the clearing devices protrude laterally from the drive unit. The "kick-back" occurs exactly as with the other known brush cutters. The Freischnei¬ ders is difficult to handle, since the device is held by handles on the power transmission device - H -

must, which does not allow safe guidance of the device. Retrofitting to a chainsaw is only possible with great effort.

From DE-OS 34 23 428 the proposal is known to use the saw chain of a chainsaw as a drive chain for a wedge splitter.

DE-OS 31 18 557 discloses a hydraulically driven chain saw for limbing.

The object of the invention is to provide an attachment of the type mentioned at the outset, which allows simple and inexpensive retrofitting of all known chain saws to a brush cutter or the like. as well as an equally inexpensive retrofitting to a chainsaw is permitted.

In addition, a "kick-back" -free use of the free cutter should be made possible; the brush cutter should be safe and easy to use.

According to the invention, the features of claim 1 serve to achieve the object.

Advantageous configurations are defined in the subclaims.

According to the invention, not only the drive motor but also the sprocket of the chain saw seated on the motor shaft is used. Only the saw blade is used for converting the chainsaw and the saw chain is removed, whereupon a fastening element can be mounted instead of the saw blade. The saw blade fastening bolts of the chain saw can also be used to assemble the fastening element. The second toothed ring, which connects the drive motor of the chain saw to the power transmission device, can be mounted on the fastening element. In order to complete the conversion, only one drive chain then has to be placed over both sprockets. The retrofitting is correspondingly simple, in which only the fastening element and the drive chain have to be removed and the saw bar and saw chain have to be reassembled.

Since the power transmission device to the free cutting head or the like. The handles and emergency shutdown devices of the chain saw can be used unchanged from the front side of the chain saw, approximately extending the longitudinal axis of the chain saw. For easier handling, a simple additional handle is added to the power transmission device, which can be coupled to the emergency cut-off device of the chain saw (for example by a simple cable pull). The chain saw, converted into a brush cutter, can be easily held and guided. Handling is even easier when using a holding and guiding belt, which can be provided with a handle.

The power transmission to the brush head or the like. can be done mechanically, using two bevel gears. One of the angular gears is connected directly to the second ring gear and sits on the front of the chain saw; In addition to its power transmission function, it therefore also ensures that the power transmission device lies approximately on the main chain saw axis. In this case, the force transmission device can consist of a casing tube and a shaft rotatable therein.

At the free end of the power transmission device there is a second angular gear, which is connected to the shaft and the circular saw blade of the brush cutter head. Alternatively, a flexible drive shaft can be used here. The parts required for the conversion are simple, inexpensive commercially available elements. Therefore, although a full brush cutter is obtained through the retrofit, the cost is minimal.

To convert the chainsaw, you only need a key for the saw blade fastening bolts.

The brush cutter according to the invention allows a particularly favorable ergonomic work posture adapted to the user with an unprecedented safety standard through the use of the handle of the chain saw or the holding and guide belt.

When a chainsaw converted according to the invention is, as described in the already mentioned documents EP 0 070 361 and DE-GM 86 24 827.8, a further, considerable advantage results from the fact that the occurrence of jumps with gripping voices occurs due to the stop which can be displaced in the axial direction of the device "Kick-back" effects are completely excluded. In addition, the fastening stop with protective stop and circular saw blade that is present in the chain saw can then simply be used as a free cutting head. This further simplifies the conversion.

The brush cutter or the like. can be attached to the power transmission device so as to be rotatable about a pivot point, as a result of which its position in the circumferential plane of the cutting elements can be optimally adapted to the cutting conditions. In addition, a pivoting of the head perpendicular to this plane relative to the power transmission device can be seen, which facilitates the forward cutting.

Instead of the mechanical power transmission device, a hydraulic power transmission device can also be used, in which case hydraulic piston motors, gear pumps or the like are used instead of the angular gear. will use. A further advantage is hereby achieved, since instead of the mechanical, direct power transmission, a hydraulic power transmission is used, which results in a gear-like effect. When the cutting resistance on the brush cutter head increases, the torque is adjusted hydraulically. In addition, this design of the power transmission device allows, in a particularly simple manner, the free cutting head in relation to the power transmission device. - t

to make pivoting so that the working angle of the brush cutter can be adapted to the movement of the brush cutter during the work process.

Instead of a clearing head, other working heads can of course also be coupled to the power transmission device. Thus, according to the invention, a chainsaw can also be converted to a cutter for grass or other green plants, for example, by attaching a thread head. For other applications, chopping heads, flail heads, brush heads, snow milling heads and other such elements can be attached.

A preferred embodiment of the invention is described in more detail below with reference to the accompanying drawing. In it show:

1 shows a schematic top view of a chainsaw converted to a brush cutter;

Fig. 2 is a schematic side view of the

Front end of the power transmission device with a cutting head attached thereon, and

Fig. 3 shows a section of the gripping area of the brush head.

The embodiment shown in FIGS. 1 to 3 is created by combining the attachment 1 according to the invention with a known chain saw 2. - 3-

To do this, the saw blade and the chain of chain saw 2 are removed. Instead of the saw blade, a fastening element (not shown) is screwed onto the body of the chainsaw 2. The fastening element is a plate-like part with holes through which the chain sword fastening bolts of the chain saw 2 are guided. The fastening element can thus be installed in place of the chain sword, for which purpose only a corresponding key is required. In Fig. 1, the fastening element lies under a chain cover 8 and a sprocket cover 10.

On the part of the fastening element protruding from the front of the chainsaw 2, a toothed ring is mounted, which is covered by the cover 10 in FIG. 1. A drive chain runs from the sprocket on the motor shaft of the chain saw to this second front sprocket. The drive chain corresponds to the saw chain of chain saw 2 except for the fact that the drive chain has no saw teeth.

Also at the free end of the fastener, a first bevel gear 12 is arranged so that it is immediately in front of the front of the chainsaw 2. The driven shaft of the first angular gear 12 is directly connected to the second ring gear. The output shaft of the first angular gear 12 points forward away from the front of the chain saw 2 and is coupled to a shaft of a power transmission device 14. The - _ -

In addition to the shaft (not shown), power transmission device 14 includes a jacket tube which surrounds the shaft on the outside, through which the shaft, which is covered and protected in this way, extends as far as a front, free end of the power transmission device 14. In the exemplary embodiment, the shaft lies parallel to the extension of the main axis of the chain saw 2.

A (second) angular gear 16 is also provided at the other end of the power transmission device 14. This is connected on the drive side to the shaft and on the output side to a circular saw blade 20 of a clearing head 22 and screwed to the clearing head. During operation, the drive motor of the chainsaw 2 therefore drives the circular saw blade 20 via its chain sprocket, the drive chain, the second sprocket, the first bevel gear 12, the shaft of the power transmission device 14 and the second bevel gear 16.

The clearing head is mounted rotatably about a pivot point 36 in the circumferential plane of the circular saw blade 20 relative to the force transmission device 14 and could, for example, be moved into its rotational position by an adjusting device. In the exemplary embodiment, a spring device (not shown) is provided instead, which urges the clearing head into the position shown in FIG. 1. The spring force is selected so that the head does not make any unintentional rotary movements.

The clearing head 22 essentially corresponds _ -si Λ -

the configuration of the saw blade and stop devices, which are described in detail in DE-GM 86 24 827.8. Reference is therefore expressly made to this publication. In particular, the clearing head 22 comprises a stop device 18 with a stop 24 which can be displaced between a gripping position (as shown) and a cutting position approximately along the axis of the force transmission device 14. This shift is indicated in FIG. 1 by arrow 28; the end positions of the movement of the stop device 18 are also shown in FIGS. 1 and 2 (dashed lines).

The approximately circular arc-shaped front edge of the stop 24 is provided with gripping projections 25 which are inclined against the direction of rotation of the circular saw blade 20. The gripping projections serve for gripping and holding branches and the like. When the free cutter is advanced, the branches gripped in this way come back into contact with the teeth of the circular saw blade 20 not displaced in the process, with the stop device 18 retracting towards the chain saw 2, and are cut cleanly, continuously being gripped by the gripping projections 25 are held. In this way the occurrence of the "kick-back" effect is excluded.

The shape of the gripping projections (FIG. 3) serves, on the one hand, to allow the material to be cut to run in easily between the gripping projections, on the other - AZ -

to ensure the safe holding of the clippings when cutting.

The one flank 38 of each gripping projection 25, which touches and holds the clippings during cutting, is inclined against the circumferential direction of the cutting elements at a holding angle fό of less than 90 ° against the adjacent peripheral edge 42 of the stop 24. The clippings are forced into this sharp bracket when cutting, so that they cannot dodge.

The rear, second flank 40 of the same gripping projection 25 faces away from the clippings held and guides incoming clippings to the gripping projection following in the circumferential direction. This second flank 40 is inclined against the circumferential direction at an entry angle - of 45 ° or less against an imaginary line 44 which runs through the gripping projection 25 in the plane of the gripping projection 25 essentially perpendicular to the peripheral edge 42. This facilitates the entry of the clippings.

In this embodiment, the clearing head 22 can be fastened directly to the chain saw 2 after removal of the fastening element as well as the power transmission device 14 and the angular gear 12, 16, as is shown in the aforementioned DE-GM 86 24 827.8. After placing the drive chain and attaching the associated chain cover, the retrofitting to the chainsaw is complete. In this embodiment, an additional handle (not shown) can be mounted at the location designated by reference numeral 30 in FIG. 1, which makes it easier to hold the device ergonomically; the device is then held and guided either on this handle and the handle 4 or the handle 6 of the chainsaw 2. In terms of its handling, it therefore corresponds to a compact device in every respect; In addition, the handle 30, which is then designed to be pivotable in the forward direction of the device, can be connected to an emergency shutdown device of the chain saw, so that operational safety during operation is completely guaranteed.

Even more advantageously, a holding and guiding belt 32 is attached to one of the handles 4 or 6, on the one hand, and on the other hand near the free end to the tubular casing of the power transmission device 14, so that the user can carry the device on the shoulder. The belt 32 has a handle 34 for guiding the device. The handle 34 is adjustable in length, as is the strap 32, if necessary, which enables adaptation to the size of the user.

Claims

Attachment device for converting a hand-operated motor chain saw

1. Attachment device for converting a hand-operated motor chain saw into a brush cutter or the like, characterized by a fastening element which can be fixed on the motor chain saw (2) and which is designed as a plate-like part which replaces the chain sword, and one from the front of the chain saw (2) extending elongated force transmission device (14), which is fixed at one end to the fastening element and with the sprocket of the chainsaw by a chain and - AS-

a second ring gear is connected, and carries a free cutting head or the like (22) at the other free end.

2. Attachment according to claim 1, characterized in that the fastening element is provided with through holes for receiving the chain sword fastening bolts.

3. Attachment according to claim 1 or 2, characterized in that the force transmission device (14) has a tubular casing, in the interior of which the force transmission elements run.

4. Attachment device according to one of claims 1 to 3, characterized in that the force transmission device (14) extends substantially parallel to or coaxially with the chain saw longitudinal axis.

5. Attachment according to one of claims 1 to 4, characterized in that the second ring gear is mounted on the fastening element and a cover (8, 10) is provided which covers the ring gears and the drive chain on the outside.

6. Attachment according to one of claims 1 to 5, characterized in that the drive chain speaks ent¬ except for the absence of saw teeth of the saw chain.

7. attachment according to one of claims 1 to 6, - 4b-

characterized in that the power transmission device (14) has a shaft as the power transmission element.

8. attachment according to claim 7, characterized in that the shaft is connected at both ends of the power transmission device (14) with an angular gear (12, 16).

9. Attachment according to claim 8, characterized in that an angular gear (16) or the like at the free end of the power transmission device (14) with the brush cutter head. (22) is screwed.

10. Attachment according to claim 7, characterized in that the power transmission device (14) or the like at the free end with a flexible drive shaft for driving the brush cutter head. (22) is provided.

11. Attachment according to one of claims 8 to 10, characterized in that a first Winkelge¬ gear (12) is arranged on the fastening element so that it carries the second chain sprocket on its driven shaft and the output side with the shaft, preferably coaxially, is connected, the angular gear (12) preferably being arranged on the front of the chain saw (2).

12. Attachment device according to one of claims 1 to 6, characterized in that the power transmission A

Device (14) is part of a hydraulic circuit.

13. Attachment device according to claim 12, characterized in that the force transmission device (14) is connected at the end to at least one hydraulic piston motor, a gear pump or the like.

14. Attachment device according to one of claims 1 to 13, characterized in that the brush cutter or the like. (22) about a pivot point (36) relative to the power transmission device (14) is rotatably or pivotably mounted on the latter.

15. Attachment device according to claim 14, characterized in that the brush cutter or the like. (22) is urged by a spring into a basic position with respect to the power transmission device (14).

16. Attachment according to one of claims 1 to 15, characterized in that at the free end of the power transmission device (14) a Freischneid¬ head (22) with a circular saw blade (20) driven by the power transmission device (14) and one of its cutting elements in a gripping position at least on one side, between the gripping position and a cutting position not covering the cutting elements along the feed direction of the brush cutter stop (24) is arranged. , - -

17. Attachment according to claim 16, characterized in that the stop (24) Greif¬ projections (25) for gripping and holding branches or the like, which are preferably tooth-like and inclined against the direction of rotation of the cutting elements, the front Edge (42) of the stop (24) is optionally circular.

18. Front attachment according to claim 17, characterized in that one of the stop

(24) the flank (38) of the gripping projection (25) facing the clippings is inclined against the circumferential direction (ß) against the adjacent peripheral edge (42) against the circumferential direction and a flank (40) facing away from the clippings being held of the gripping projection (25) is inclined against the circumferential direction at an entry angle (o) of 45 "or more against an imaginary line (44) which is in the plane of the gripping projection

(25) extends essentially perpendicular to the peripheral edge (42) through the gripping projection (25).

19. Front attachment according to one of claims 16 to 18, characterized in that the stop (24) is urged by a spring device into the gripping position.

20. Attachment device according to one of claims 1 to 19, characterized in that at the front end of the power transmission device (14) is arranged a line head driven by this. - ". <) -

21. Attachment device according to one of claims 1 to 19, characterized in that at the front end of the power transmission device (14) is driven by this an¬ chopped head, a chopper head, a snow blower head, a brush head or the like.

22. Attachment device according to one of claims 1 to 21, characterized in that the brush cutter or the like is arranged pivotably on the power transmission device (14) relative to the longitudinal axis of the force transmission device (14), preferably a possibly spring-loaded adjusting device for the Swivel position of the head is seen.

23. Attachment device according to one of claims 1 to 22, characterized in that a handle (at 30) is provided in front of the chainsaw (2), in particular on the fastening element or on the power transmission device (14), which if necessary with an emergency stop switching device of the chainsaw (2) is coupled.

24. Front attachment according to one of claims 1 to 23, characterized in that a holding and guide belt (32) on the one hand on the motor chain saw (2) and on the other hand on the power transmission device (14) or on the clearing head or the like. (22) can be fastened.

25. Attachment according to claim 24, characterized in that the belt (32) one- - iς> -

on the one hand on a handle (4 or 6) of the motor chain saw (2), on the other hand on the casing tube of the power transmission device (14) can be fastened.

26. Front attachment according to claim 24 or 25, characterized in that the holding and guide belt (32) is provided with a movable, in particular length-adjustable handle (34).