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EP2447022B1 - Chain brake device for a chain saw operated by pressurised air - Google Patents

Chain brake device for a chain saw operated by pressurised air Download PDF

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Publication number
EP2447022B1
EP2447022B1 EP10189385A EP10189385A EP2447022B1 EP 2447022 B1 EP2447022 B1 EP 2447022B1 EP 10189385 A EP10189385 A EP 10189385A EP 10189385 A EP10189385 A EP 10189385A EP 2447022 B1 EP2447022 B1 EP 2447022B1
Authority
EP
European Patent Office
Prior art keywords
chain
compressed air
saw
brake
braking
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
EP10189385A
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German (de)
French (fr)
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EP2447022A1 (en
Inventor
Simon Witt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Spitznas Maschinenfabrik GmbH
Original Assignee
Spitznas Maschinenfabrik GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
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Priority to PL10189385T priority Critical patent/PL2447022T3/en
Priority to EP10189385A priority patent/EP2447022B1/en
Publication of EP2447022A1 publication Critical patent/EP2447022A1/en
Application granted granted Critical
Publication of EP2447022B1 publication Critical patent/EP2447022B1/en
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27B—SAWS FOR WOOD OR SIMILAR MATERIAL; COMPONENTS OR ACCESSORIES THEREFOR
    • B27B17/00—Chain saws; Equipment therefor
    • B27B17/08—Drives or gearings; Devices for swivelling or tilting the chain saw
    • B27B17/083—Devices for arresting movement of the saw chain

Definitions

  • the invention relates to a method for braking a motorized chainsaw, with compressed air driven chain drive, through which the saw chain is driven.
  • chainsaws are used for the mentioned fields of application that do not require an electric drive or an internal combustion engine.
  • These chainsaws use a pneumatic drive. With compressed air, a pneumatic motor of the chain saw is driven.
  • the chain saws have a braking device that engages when a trigger mechanism is actuated.
  • the compressed air-driven drive is connected to a brake drum.
  • the brake drum is looped around by a brake band.
  • the trigger mechanism is activated, the brake band becomes The DE 3232775 A1 describes, for example, a braking device for braking the saw chain of a portable motor chain saw.
  • the motor chain saw has a sensor that responds when a dangerous condition occurs.
  • the senor is formed as in a spin movement of the saw with a hand of the saw guide on the housing of the chain saw rotatably held hand protection lever.
  • a friction brake is actuated which acts on a drum connected to the drive sprocket of the chain saw.
  • the friction brake is provided with a safety device which actuates the friction band brake even when an uncontrolled acceleration of the revolving saw chain occurs.
  • the DE 3316899 A1 discloses a chainsaw with a housing. On the case a handle is mounted. A motor is received in the housing, with a cutting chain having a housing extending from the extending bearing rail for supporting the cutting chain for endless movement. The chain saw further has a drive connection with the motor, which is provided with a rotation transmission device for driving the cutting chain. A safety brake device serves to stop the cutting chain. In this case, the safety brake device has a sensor arm pivotally mounted on the housing. A part of the feeler arm lies in front of the handle during operation of the chain saw. The feeler arm is movable from a first position to a second position.
  • a flexible brake band secured to the housing at a first end and coupled to the projection at a second end such that upon movement of the sensor arm from the first position to the second position, the flexible brake band is displaced from a position free of the rotational transmission device a friction-braking relationship is moved with the rotation transmission device.
  • the DE 3419152 A1 describes a Kettenbremsvornchtung for actuating a spring-loaded brake for devices with a drive motor, in particular motor chain saw.
  • the chain brake device in this case has a trigger, which is connected to a tensioning and braking member, wherein the braking member is disposed on a braking band surrounding a brake drum.
  • a latching device is held against the force of an attacking brake spring in a standby position, in the brake band is lifted from the brake drum, and in which the clamping member in the braking position of the brake member in the path of movement of a driver can be brought.
  • a safety brake system for a chain saw is disclosed.
  • a pivotable member which has a spaced apart from the lower end portion of a brake lever of a brake handle arm.
  • the handle is pivotally mounted on a front handle and is actuated by the brake lever when it is pivoted.
  • An arm of a fork of the pivotable member is connected to one end of a brake band, which is looped over the outer periphery of a clutch drum of a centrifugal clutch.
  • the chainsaw is driven, while the other arm of the fork is prevented by a locking lever on a pivoting movement.
  • Chainsaws with pneumatic drive are already marketed under the product designations Chainsaw 510210020, 510220020 and 510230020 by the applicant.
  • the field of application varies from underwater use, plastic cutting to mining.
  • These chainsaws have a braking system, such as described above.
  • Disadvantage of the known brake systems for pneumatic chain saws is that the braking behavior is relatively slow. This jeopardizes the safety of the legendary leader in unfortunate circumstances.
  • the EP 0018603 discloses machines, in particular a chainsaw, which are operated with compressed air.
  • the saw chain is driven by a pneumatic chain drive.
  • Compressed air control means support the braking process for the saw chain.
  • the disadvantage with this braking device is that it does not react fast enough
  • the object is also achieved by a method of the type mentioned above for braking a motor-driven chainsaw, in which the compressed air supply is controlled for braking, wherein the compressed air supply is reversed.
  • the braking effect is caused solely by the friction brake.
  • the friction brake acts at the moment of triggering directly against the compressed air drive. This increases the wear of the brake. It always has to work against the drive.
  • the compressed air supply is controlled when triggered. For example, the compressed air supply can be reduced. The appropriate control of the compressed air flow both in quantity, as well as flow direction can greatly assist the braking effect of a pneumatic chain saw.
  • the compressed air control means are designed as a breaker valve. Often it is sufficient for the compressed air-driven chainsaws to prevent the driving compressed air with a stroke. Between the compressed air drive and the compressed air supply, an interrupter valve is arranged. By triggering the breaker valve, the further inflow of compressed air is prevented. Thus, the friction brake is no longer working against the compressed air drive. The temporal braking behavior of the chainsaw is considerably shortened.
  • the embodiment of the invention is that the compressed air control means cause a reversal of the direction of the compressed air.
  • the direction of the compressed air is changed, so that the compressed air-driven drive experiences a kind of thrust reversal.
  • This ensures that the friction brake not only works against the compressed air, but is considerably supported by the compressed air.
  • the control means must thus be designed so that the drive can change direction. Both direction reversal and interruption of compressed air can be used in combination. Because it may be necessary that initially the direction of the compressed air for the drive is reversed. Finally, in order to prevent the chain from also moving in the opposite direction, it is necessary to interrupt the supply of compressed air by means of the interrupting valve. The direction reversal of the compressed air can or should therefore be limited in time.
  • a preferred embodiment of the invention is also that the compressed air control means are actuated by a triggering device.
  • a triggering device Especially in emergencies, it is necessary that the chain saw chain stops immediately to avoid major accidents.
  • a system must be present, which actuates the brake means directly.
  • the triggering device may for example contain a sensor, such as an acceleration sensor, which registers extraordinary changes in direction and directly actuates the brake device of the chain saw.
  • the triggering device is therefore coupled to a triggering mechanism for triggering the braking means.
  • the triggering mechanism is preferably formed mechanically, so as not to cause any danger.
  • the triggering mechanism then includes a mechanical brake lever, wherein the brake lever is provided as a hand guard. In an emergency, the saw driver can brake the saw by hand by activating the hand guard to release the brake.
  • the braking means are biased. Due to the bias, which is generated for example by springs, the friction brake is applied extremely quickly to the brake drum.
  • the brake means comprise a brake band, which wraps around the brake drum.
  • Brake bands are not only easy to implement in assembly and production, they are also extremely lightweight, insensitive and easy to maintain.
  • the compressed air control means are designed as a breaker valve. Again, the interruption of the supply for the compressed air prevents the braking effect of the friction brake works against the compressed air.
  • the embodiment of the motorized chainsaw according to the invention is that the compressed air control means cause a reversal of direction of the compressed air direction.
  • the direction of the compressed air is changed in order to pressurize the compressed air-driven drive with a force against the previous direction. This causes a braking effect on the direction reversal.
  • a friction brake is supported if necessary considerably by this measure.
  • the compressed air supply is interrupted. At the moment when the compressed air supply is interrupted, the chain saw powered by compressed air is no longer driven. Thus, the friction brakes are not stressed so much, because they no longer have to work against the compressed air flow.
  • the interruption of the compressed air supply is equal to a complete shutdown of the drive.
  • the erfindungsgenzeße method for braking a motor-driven chainsaw results from the fact that the compressed air supply is reversed. By this measure it is achieved that a friction brake is significantly supported by the braking power of the drive or even makes a friction brake unnecessary.
  • FIG. 1 shows a schematic diagram of a pneumatic chain saw 10 with a chain brake device 12 in section.
  • the pneumatic chain saw 10 has a housing 14. On the housing 14, a first handle and operating area 16 and a second 18 are provided. On the housing 14, a sword is mounted on an end face 20. The sword is not shown in the present figures. A saw chain, also not shown, runs around the sword in a known manner. For this purpose, suitable guide grooves are provided.
  • the chain drive 22 consists of a compressed air from a motor 24 (see Fig. 2 ), which is coupled with a likewise not shown Kettenantriebsrad.
  • the pneumatic motor 24 often consists of a vane motor.
  • the vane motor has a substantially cylindrical housing in which the rotor is rotatably mounted with a shaft. Slats are provided on the rotor.
  • the cylindrical housing has at least one inlet and one outlet opening.
  • On the shaft of the rotor is a gear, which drives the Kettenantriebsrad. If necessary, can be dispensed with a transmission. Then the Kettenantriebsrad is located directly on the shaft of the rotor.
  • the compressed air is generated by means of a compressor and passed through a compressed air hose to the chainsaw 10.
  • the inlet opening of the compressed air motor 24 is provided with a suitable nozzle 25 to which the compressed air hose can be connected. Due to the compressed air flow, the rotor is set in motion to drive.
  • a brake drum 28 is also connected to the drive.
  • the brake drum 28 is part of the chain brake device 12.
  • the brake drum 28 rotates according to the rotor of the chain drive 22.
  • a brake band 30 is looped.
  • Brake drum 28 and brake band 30 form a friction brake 31, which tries to decelerate the chain drive 22 by friction.
  • a mechanical release mechanism 32 is disposed on the chain saw 10.
  • the triggering mechanism 32 has a lever chain 34 and a brake lever 36, which is designed as a hand guard 38.
  • the lever chain 34 has a transmission member 39 and a brake band lever 41.
  • the brake lever 36 is biased by the lever chain 34 with a tension spring 45.
  • the tension spring 45 is attached to the brake band lever 41.
  • the brake band lever 41 can be pivoted about an axis of rotation 43. In a first position of the brake lever 36, the brake band 30 is loose, so that the Kettenantriebsrad and the brake drum 30 can rotate freely.
  • the brake band In a second and braking position of the brake lever 36, the brake band is contracted.
  • the brake drum 28 is braked by friction with the brake band 30.
  • the chain brake device 12 By releasing the trigger mechanism 32, the chain brake device 12 is transferred from the free running first position to a braking second position. This release of the braking operation is performed manually by operating the brake lever 36.
  • Fig. 3 the two adjustment positions of the friction brake are shown schematically.
  • the brake lever 36 When the brake lever 36 is pushed forward, the brake band 30 is contracted and the brake drum 28 is braked by friction.
  • the brake lever 36 When the brake lever 36 is pulled back, the brake band 30 is released.
  • the Brake drum 28 and thus coupled to the brake drum 28 chain drive 22 can run free.
  • the brake lever 36 is connected to a first compressed air valve 42.
  • the compressed air valve 42 is a control means 44, which in the present Aus spaihrungsbeispiel two states knows: "open” - for ongoing operation and "locked” during the braking process.
  • the first compressed air valve 42 shuts off the supply of compressed air as soon as the brake lever 36 is actuated from the first to the second braking position.
  • An adjusting lever 46 is connected to the compressed air valve 42 for manual release with the brake lever 36.
  • the brake lever 36 and the adjusting lever 46 form a triggering device 48.
  • the friction brake 31 not against the chain drive 22, which is otherwise driven by the compressed air flow.
  • the braking behavior is significantly reduced by the blocking of the first compressed air valve 42.
  • a second compressed air valve 50 is provided in addition to the first compressed air valve 42.
  • This second compressed air valve 50 is used in normal operation for starting and stopping the chain drive 22.
  • This compressed air valve 50 is not connected to the friction brake.
  • control means 44 are also designed so that they cause a temporary reversal of direction instead of the complete shut-off of the compressed air flow.
  • the braking process is additionally supported by the compressed air flow.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Forests & Forestry (AREA)
  • Sawing (AREA)

Description

Technisches GebietTechnical area

Die Erfindung betrifft eine Kettenbremseinrichtung für eine motorbetriebene Kettensäge, enthaltend

  1. a) eine Sägekette, welche in einer Kettenführung der Kettensäge beweglich geführt wird,
  2. b) einen druckluftbetriebenen Kettenantrieb, durch den die Sägekette angetrieben wird,
  3. c) eine Bremstrommel, welche mit dem Kettenantrieb verbundenen ist und
  4. d) auslösbare Bremsmittel, welche durch Reibung zum Bremsen der Bremstrommel vorgesehen sind,
  5. e) Druckluftsteuerungsmittel zur Steuerung des Druckluftstroms bei der druckluftbetriebenen Kettensäge, welcher den Bremsvorgang der Kettensäge über den druckluftbetriebenen Kettenantrieb unterstützen,
  6. f) eine Auslösevorrichtung zur Betätigung der Druckluftsteuerungsmittel,
  7. g) die Auslösevorrichtung mit einem Auslösemechanismus zum Auslösen der Bremsmittel gekoppelt ist.
The invention relates to a chain brake device for a motorized chainsaw, containing
  1. a) a saw chain, which is movably guided in a chain guide of the chain saw,
  2. b) a pneumatic chain drive which drives the saw chain,
  3. c) a brake drum which is connected to the chain drive and
  4. d) releasable brake means, which are provided by friction for braking the brake drum,
  5. e) compressed air control means for controlling the compressed air flow in the air powered chain saw, which aid in the braking operation of the chain saw via the air driven chain drive,
  6. f) a triggering device for actuating the compressed air control means,
  7. g) the triggering device is coupled to a triggering mechanism for triggering the braking means.

Ferner betrifft die Erfindung eine motorbetriebene Kettensäge, enthaltend

  • a) eine Sägekette, welche in einer Kettenführung der Kettensäge beweglich geführt wird,
  • b) einen mit Druckluft betriebenen Kettenantrieb, durch den die Sägekette angetrieben wird,
  • c) eine Bremstrommel, welche mit dem Kettenantrieb verbundenen ist und
  • d) auslösbare Bremsmittel, welche durch Reibung zum Bremsen der Bremstrommel vorgesehen sind,
  • e) Druckluftsteuerungsmittel zur Steuerung des Druckluftstroms bei der druckluftbetriebenen Kettensäge, welche den Bremsvorgang über den Druckluft betriebenen Kettenantrieb zum Bremsen steuern.
Furthermore, the invention relates to a motorized chainsaw containing
  • a) a saw chain, which is movably guided in a chain guide of the chain saw,
  • b) a chain drive driven by compressed air, through which the saw chain is driven,
  • c) a brake drum which is connected to the chain drive and
  • d) releasable brake means, which are provided by friction for braking the brake drum,
  • e) Compressed air control means for controlling the compressed air flow in the air driven chain saw, which control the braking operation via the air operated chain drive for braking.

Weiterhin betrifft die Erfindung ein Verfahren zum Abbremsen einer motorbetriebene Kettensäge, mit druckluftbetriebenen Kettenantrieb, durch den die Sägekette angetrieben wird.Furthermore, the invention relates to a method for braking a motorized chainsaw, with compressed air driven chain drive, through which the saw chain is driven.

Stand der TechnikState of the art

Eine derartige Ketten blemseinrichtung, eine derartige Kettensäge und ein derartiges Verfahren gehen beispielsweise aus der EP 0018 603 hervor.Such a chain blemseinrichtung, such a chainsaw and such a method, for example, from the EP 0018 603 out.

Gefahrenstoffe, sei es fester, flüssiger oder gasförmiger Natur, die leicht entzündlich sind, können durch Funkenflug schnell explodieren bzw. brennen. In solchen Bereichen, wo solche Stoffe vorhanden sind, dürfen aufgrund von Funkenbildung keine elektrischen Geräte oder Verbrennungsmaschinen verwendet werden. Zu diesen Bereichen zählen insbesondere z.B. der Bergbaus oder die Petro- bzw. Chemieindustrie. Auch unter Wasser können solche Werkzeuge nicht verwendet werden. Viele Werkzeuge arbeiten aber mit einem elektrischen Antrieb oder Verbrennungsmotor, um entsprechende Leistung aufbringen zu können. Dazu zählen auch Kettensägen. Kettensägen finden in vielen dieser industriellen Bereiche ihr Anwendungsgebiet. Auch sie müssen so ausgestaltet sein, dass kein Funkenflug entsteht.Hazardous substances, whether solid, liquid or gaseous in nature, which are highly flammable, can quickly explode or burn due to flying sparks. In such areas where such materials are present, no electrical equipment or combustion engines may be used due to sparking. These ranges include, in particular, e.g. mining or the petrochemical or chemical industry. Even underwater, such tools can not be used. However, many tools work with an electric drive or internal combustion engine in order to be able to apply appropriate power. These include chainsaws. Chainsaws find their application in many of these industrial sectors. They too must be designed so that no flying sparks occur.

Es werden daher Kettensägen für die genannten Anwendungsgebiete eingesetzt, die keinen elektrischen Antrieb oder Verbrennungsmotor benötigen. Diese Kettensägen benutzen einen Druckluftantrieb. Mit Druckluft wird ein Druckluftmotor der Kettensäge angetrieben. Zur Sicherheit verfügen die Kettensägen eine Bremseinrichtung, die bei Betätigung eines Auslösemechanismus greift. Dazu ist der druckluftbetriebene Antrieb mit einer Bremstrommel verbunden. Die Bremstrommel wird von einem Bremsband umschlungen. Wird der Auslösemechanismus betätigt, so wird das Bremsband Die DE 3232775 A1 beschreibt beispielsweise eine Bremsvorrichtung zum Abbremsen der Sägekette einer tragbaren Motorkettensäge. Hierzu verfügt die Motorkettensäge über einen Fühler, der bei Auftreten eines Gefahrenzustandes anspricht. Dabei ist der Fühler als bei einer Schleuderbewegung der Säge mit einer Hand des Sägenfülhrers an dem Gehäuse der Kettensäge drehbar gehaltener Handschutzhebel ausgebildet. Durch Bewegung des Handschutzhebel wird eine Reibungsbremse betätigt, die auf eine mit dem Antriebskettenrad der Kettensäge verbundene Trommel einwirkt. Die Reibungsbremse ist mit einer Sicherheitseinrichtung versehen, die auch bei Auftreten einer unkontrollierten Beschleunigung der umlaufenden Sägekette die Reibungsbandbremse betätigt.Therefore, chainsaws are used for the mentioned fields of application that do not require an electric drive or an internal combustion engine. These chainsaws use a pneumatic drive. With compressed air, a pneumatic motor of the chain saw is driven. For safety, the chain saws have a braking device that engages when a trigger mechanism is actuated. For this purpose, the compressed air-driven drive is connected to a brake drum. The brake drum is looped around by a brake band. When the trigger mechanism is activated, the brake band becomes The DE 3232775 A1 describes, for example, a braking device for braking the saw chain of a portable motor chain saw. For this purpose, the motor chain saw has a sensor that responds when a dangerous condition occurs. In this case, the sensor is formed as in a spin movement of the saw with a hand of the saw guide on the housing of the chain saw rotatably held hand protection lever. By moving the hand guard lever, a friction brake is actuated which acts on a drum connected to the drive sprocket of the chain saw. The friction brake is provided with a safety device which actuates the friction band brake even when an uncontrolled acceleration of the revolving saw chain occurs.

Die DE 3316899 A1 offenbart eine Kettensäge mit einem Gehäuse. Auf dem Gehäuse ist ein Handgriff montiert. In dem Gehäuse ist ein Motor aufgenommenen, wobei eine Schneidkette, mit einer sich vom Gehäuse nach vom erstreckenden Lagerschiene zur Lagerung der Schneidkette für eine endlose Bewegung vorgesehen ist. Die Kettensäge verfügt ferner über eine Antriebsverbindung mit dem Motor, welche mit einer Drehübertragungsvorrichtung für den Antrieb der Schneidkette vorgesehen ist. Eine Sicherheits-Bremsvorrichtung dient zum Anhalten der Schneidkette. Dabei weißt die Sicherheits-Bremsvorrichtung einen am Gehäuse schwenkbar gelagerten Fühlerarm auf. Ein Teil des Fühlerarms liegt während des Betriebs der Kettensäge vor dem Handgriff. Der Fühlerarm ist aus einer ersten Position in eine zweite Position bewegbar. Ein flexibles Bremsband, das mit einem ersten Ende am Gehäuse befestigt ist und mit einem zweiten Ende mit dem Vorsprung derart gekuppelt ist, dass bei einer Bewegung des Fühlerarmes aus der ersten Position in die zweite Position das flexible Bremsband aus einer von der Drehübertragungsvorrichtung freien Position in eine Reibungs-Bremsbeziehung mit der Drehübertragungsvorrichtung bewegt wird.The DE 3316899 A1 discloses a chainsaw with a housing. On the case a handle is mounted. A motor is received in the housing, with a cutting chain having a housing extending from the extending bearing rail for supporting the cutting chain for endless movement. The chain saw further has a drive connection with the motor, which is provided with a rotation transmission device for driving the cutting chain. A safety brake device serves to stop the cutting chain. In this case, the safety brake device has a sensor arm pivotally mounted on the housing. A part of the feeler arm lies in front of the handle during operation of the chain saw. The feeler arm is movable from a first position to a second position. A flexible brake band secured to the housing at a first end and coupled to the projection at a second end such that upon movement of the sensor arm from the first position to the second position, the flexible brake band is displaced from a position free of the rotational transmission device a friction-braking relationship is moved with the rotation transmission device.

Die DE 3419152 A1 beschreibt eine Kettenbremsvornchtung zum Betätigen einer federbelasteten Bremse für Geräte mit einem Antriebsmotor, insbesondere Motorkettensäge. Die Kettenbremsvorrichtung weist dabei einen Auslöser auf, der mit einem Spann- und Bremsglied verbunden ist, wobei das Bremsglied an einem eine Bremstrommel umgebenden Bremsband angeordnet ist. Eine Rasteinrichtung ist gegen die Kraft einer an ihn angreifenden Bremsfeder in einer Bereitschaftsstellung gehalten, in der das Bremsband von der Bremstrommel abgehoben ist, und bei der das Spannglied in Bremsstellung des Bremsgliedes in den Bewegungsweg eines Mitnehmers bringbar ist.The DE 3419152 A1 describes a Kettenbremsvornchtung for actuating a spring-loaded brake for devices with a drive motor, in particular motor chain saw. The chain brake device in this case has a trigger, which is connected to a tensioning and braking member, wherein the braking member is disposed on a braking band surrounding a brake drum. A latching device is held against the force of an attacking brake spring in a standby position, in the brake band is lifted from the brake drum, and in which the clamping member in the braking position of the brake member in the path of movement of a driver can be brought.

In der DE 000003427144 A1 wird ein Sicherheitsbremssystem für eine Kettensäge offenbart. Bei der Kettensäge ist ein schwenkbares Organ vorgesehen, welches einen im Abstand zum unteren Endabschnitt eines Bremshebels eines Bremshandgriffs angeordneten Arm aufweist. Der Handgriff ist dabei schwenkbar an einem Frontgriff befestigt und wird durch den Bremshebel betätigt, wenn dieser verschwenkt wird. Ein Arm einer Gabel des schwenkbaren Organs ist mit einem Ende eines Bremsbandes verbunden, welches über den äußeren Umfang einer Kupplungstrommel einer Zentrifugalkupplung geschlungen ist. Über die Zentrifugalkupplung wird die Kettensäge angetrieben, während der andere Arm der Gabel durch einen Verriegelungshebel an einer Schwenkbewegung gehindert ist.In the DE 000003427144 A1 a safety brake system for a chain saw is disclosed. In the chain saw, a pivotable member is provided which has a spaced apart from the lower end portion of a brake lever of a brake handle arm. The handle is pivotally mounted on a front handle and is actuated by the brake lever when it is pivoted. An arm of a fork of the pivotable member is connected to one end of a brake band, which is looped over the outer periphery of a clutch drum of a centrifugal clutch. About the centrifugal clutch, the chainsaw is driven, while the other arm of the fork is prevented by a locking lever on a pivoting movement.

Unter den Produktbezeichnungen Kettensäge 510210020, 510220020 und 510230020 der Anmelderin werden bereits Kettensägen mit Druckluftantrieb vertrieben. Das Verwendungsgebiet variiert dabei von Unterwassereinsatz, Kunststoff schneiden bis hin zum Bergbau. Diese Kettensägen verfügen über ein Bremssystem, wie es beispielsweise oben beschrieben wurde. Nachteil bei den bekannten Bremssystemen für druckluftbetriebene Kettensägen ist, dass das Abbremsverhalten relativ langsam ist. Dadurch wird die Sicherheit des Sagenführers unter unglücklichen Umständen gefährdet.Chainsaws with pneumatic drive are already marketed under the product designations Chainsaw 510210020, 510220020 and 510230020 by the applicant. The field of application varies from underwater use, plastic cutting to mining. These chainsaws have a braking system, such as described above. Disadvantage of the known brake systems for pneumatic chain saws is that the braking behavior is relatively slow. This jeopardizes the safety of the legendary leader in unfortunate circumstances.

Die EP 0018603 offenbart Maschinen, insbesondere eine Kettensäge, welche mit Druckluft betrieben werden. Die Sägekette wird dabei über einen druckluftbetriebenen Kettenantrieb angetrieben. Druckluftsteuerungsmittel unterstützen den Bremsvorgang für die Sägekette. Nachteil ist bei dieser Bremseinrichtung, dass sie nicht schnell genug reagiertThe EP 0018603 discloses machines, in particular a chainsaw, which are operated with compressed air. The saw chain is driven by a pneumatic chain drive. Compressed air control means support the braking process for the saw chain. The disadvantage with this braking device is that it does not react fast enough

Offenbarung der ErfindungDisclosure of the invention

Es ist Aufgabe der Erfindung, die genannten Probleme des Standes der Technik zu vermeiden und eine Kettenbremseinrichtung für eine motorbetriebene Kettensäge zu schaffen, die ein entsprechend schnelles Abbremsverhalten zeigt, um ein erhöhtes Maß an Sicherheit zu erreichen. Weiterhin ist es Aufgabe der Erfindung eine motorbetriebene Kettensäge zu schaffen, welche ein erhöhtes Maß an Sicherheit beim Abbremsverhalten liefert. Es ist auch als Aufgabe der Erfindung anzusehen, ein Verfahren für eine druckluftbetriebene Kettensäge zu schaffen, welches die Sicherheit bezüglich des Bremsverhaltens verbessert.It is an object of the invention to avoid the aforementioned problems of the prior art and to provide a chain brake device for a motor-driven chainsaw, which shows a correspondingly fast deceleration behavior to an increased degree to achieve safety. It is another object of the invention to provide a motorized chainsaw, which provides an increased level of safety in braking behavior. It is also to be regarded as an object of the invention to provide a method for a pneumatic chain saw, which improves the safety with respect to the braking behavior.

Erfindungsgemäß wird die Aufgabe dadurch gelöst, dass bei einer Kettenbremseinrichtung für eine motorbetriebene Kettensäge der eingangs genannten Art

  • h) die Druckluftsteuerungsmittel eine Richtungsumkehr der Druckluftrichtung bewirken und
  • i) der Auslösemechanismus einen mechanischen Bremshebel enthält, wobei der Bremshebel als Handschutzbügel vorgesehen ist.
According to the invention the object is achieved in that in a chain brake device for a motorized chainsaw of the type mentioned
  • h) the compressed air control means cause a reversal of direction of the compressed air direction and
  • i) the release mechanism includes a mechanical brake lever, wherein the brake lever is provided as a hand guard.

Weiterhin wird die Aufgabe durch eine motorbetriebene Kettensäge der eingangs genannten Art gelöst, bei der

  • f) die Druckluftsteuerungsmittel eine Richtungsumkehr der Druckluftrichtung bewirken.
Furthermore, the object is achieved by a motor-driven chainsaw of the type mentioned, in the
  • f) the compressed air control means cause a direction reversal of the compressed air direction.

Die Aufgabe wird zudem durch ein Verfahren der eingangs genannten Art zum Abbremsen einer motorbetriebene Kettensäge gelöst, bei dem die Druckluftzufuhr zum Bremsen gesteuert wird, wobei die Druckluftzufuhr umgekehrt wird.The object is also achieved by a method of the type mentioned above for braking a motor-driven chainsaw, in which the compressed air supply is controlled for braking, wherein the compressed air supply is reversed.

Bei den Bremssystemen, wie sie im Stand der Technik für druckluftbetriebene Kettensägen vorhanden sind, wird die Bremswirkung allein durch die Reibungsbremse bewirkt. Die Reibungsbremse wirkt im Moment des Auslösens unmittelbar gegen den Druckluftantrieb. Dadurch erhöht sich der Verschleiß der Bremse. Sie muss nämlich immer gegen den Antrieb arbeiten. Bei vorliegender Erfindung wird die Druckluftzufuhr beim Auslösen gesteuert. Beispielsweise kann die Druckluftzufuhr reduziert werden. Die geeignete Steuerung des Druckluftstroms sowohl in Menge, als auch Strömungsrichtung kann die Bremswirkung bei einer druckluftbetriebenen Kettensäge erheblich unterstützen.In the brake systems, as they are available in the prior art for air-driven chainsaws, the braking effect is caused solely by the friction brake. The friction brake acts at the moment of triggering directly against the compressed air drive. This increases the wear of the brake. It always has to work against the drive. In the present invention, the compressed air supply is controlled when triggered. For example, the compressed air supply can be reduced. The appropriate control of the compressed air flow both in quantity, as well as flow direction can greatly assist the braking effect of a pneumatic chain saw.

In einer vorteilhaften Ausgestaltung der erfindungsgemäßen Kettenbremseinrichtung für eine motorbetriebene Kettensäge sind die Druckluftsteuerungsmittel als Unterbrecherventil ausgebildet. Oft reicht es bei den druckluftbetriebenen Kettensägen aus, die treibende Druckluft mit einem Schlag zu unterbinden. Zwischen dem Druckluftantrieb und der Druckluftzufuhr ist ein Unterbrecherventil angeordnet. Durch Auslösen des Unterbrecherventils wird der weitere Zufluss von Druckluft unterbunden. Damit arbeitet die Reibungsbremse nicht mehr gegen den Druckluftantrieb. Das zeitliche Abbremsverhalten der Kettensäge wird erheblich verkürzt.In an advantageous embodiment of the chain brake device according to the invention for a motor-driven chain saw, the compressed air control means are designed as a breaker valve. Often it is sufficient for the compressed air-driven chainsaws to prevent the driving compressed air with a stroke. Between the compressed air drive and the compressed air supply, an interrupter valve is arranged. By triggering the breaker valve, the further inflow of compressed air is prevented. Thus, the friction brake is no longer working against the compressed air drive. The temporal braking behavior of the chainsaw is considerably shortened.

Die Ausgestaltung der Erfindung besteht darin, dass die Druckluftsteuerungsmittel eine Richtungsumkehr der Druckluftrichtung bewirken. Dabei wird die Richtung der Druckluft gewechselt, so dass der druckluftbetriebene Antrieb quasi eine Schubumkehr erfährt. Damit wird erreicht, dass die Reibungsbremse nicht nur gegen die Druckluft arbeitet, sondern wird durch die Druckluft erheblich unterstützt. Die Steuerungsmittel müssen somit so ausgelegt sein, dass der Antrieb seine Richtung wechseln kann. Sowohl Richtungsumkehr als auch Unterbrechung der Druckluft können kombiniert verwendet werden. Denn es kann erforderlich sein, die zunächst die Richtung der Druckluft für den Antrieb umgekehrt wird. Um zu verhindern, dass die Kette sich schließlich ebenfalls in die entgegengesetzte Richtung bewegt ist schließlich eine Unterbrechung der Druckluftzufuhr mittels des Unterbrecherventils erforderlich. Die Richtungsumkehr der Druckluft kann bzw. sollte demnach zeitlich begrenzt werden.The embodiment of the invention is that the compressed air control means cause a reversal of the direction of the compressed air. In this case, the direction of the compressed air is changed, so that the compressed air-driven drive experiences a kind of thrust reversal. This ensures that the friction brake not only works against the compressed air, but is considerably supported by the compressed air. The control means must thus be designed so that the drive can change direction. Both direction reversal and interruption of compressed air can be used in combination. Because it may be necessary that initially the direction of the compressed air for the drive is reversed. Finally, in order to prevent the chain from also moving in the opposite direction, it is necessary to interrupt the supply of compressed air by means of the interrupting valve. The direction reversal of the compressed air can or should therefore be limited in time.

Eine bevorzugte Ausbildung der Erfindung besteht auch darin, dass die Druckluftsteuerungsmittel durch eine Auslösevorrichtung betätigt werden. Gerade in Notfällen ist es erforderlich, dass die Kette der Kettensäge unverzüglich stoppt, zur Vermeidung größerer Unfälle. Hierfür muss ein System vorhanden seien, welches die Bremsmittel unmittelbar betätigt. Dies wird mit einer Auslösevorrichtung realisiert. Dabei kann die Auslösevorrichtung beispielsweise einen Sensor, wie einen Beschleunigungssensor, enthalten, der außergewöhnliche Richtungsänderung registriert und die Bremseinrichtung der Kettensäge unmittelbar betätigt.A preferred embodiment of the invention is also that the compressed air control means are actuated by a triggering device. Especially in emergencies, it is necessary that the chain saw chain stops immediately to avoid major accidents. For this purpose, a system must be present, which actuates the brake means directly. This is realized with a triggering device. In this case, the triggering device may for example contain a sensor, such as an acceleration sensor, which registers extraordinary changes in direction and directly actuates the brake device of the chain saw.

Sofern die Druckluft betriebene Kettensäge in explosiven Bereichen beziehungsweise unter Wasser verwendet wird, können nur mechanische Bauteile verwendet werden. In einer bevorzugten Ausgestaltung der Erfindung ist die Auslösevorrichtung daher mit einem Auslösemechanismus zum Auslösen der Bremsmittel gekoppelt. Dabei ist der Auslösemechanismus vorzugsweise mechanisch ausgebildet, um keine Gefährdung hervorzurufen. Vorzugsweise enthält der Auslösemechanismus dann einen mechanischen Bremshebel, wobei der Bremshebel als Handschutzbügel vorgesehen ist. So kann der Sägeführer im Notfall die Säge mit der Hand abbremsen, indem er den Handschutzbügel zum auslösen der Bremse betätigt.If the pneumatic chain saw is used in explosive areas or under water, only mechanical components can be used. In a preferred embodiment of the invention, the triggering device is therefore coupled to a triggering mechanism for triggering the braking means. In this case, the triggering mechanism is preferably formed mechanically, so as not to cause any danger. Preferably, the triggering mechanism then includes a mechanical brake lever, wherein the brake lever is provided as a hand guard. In an emergency, the saw driver can brake the saw by hand by activating the hand guard to release the brake.

Um eine entsprechende Kraft und Geschwindigkeit beim Bremsvorgang zu erzeugen, sind in einer bevorzugten Ausgestaltung der erfindungsgemäßen Kettenbremseinrichtung für eine motorbetriebene Kettensäge die Bremsmittel vorgespannt. Durch die Vorspannung, welche beispielsweise durch Federn erzeugt wird, wird die Reibbremse extrem schnell auf die Bremstrommel aufgebracht.In order to generate a corresponding force and speed during braking, in a preferred embodiment of the chain brake device according to the invention for a motor-driven chain saw, the braking means are biased. Due to the bias, which is generated for example by springs, the friction brake is applied extremely quickly to the brake drum.

In einer bevorzugten Ausbildung der erfindungsgemäßen Kettenbremseinrichtung enthalten die Bremsmittel ein Bremsband, welches die Bremstrommel umschlingt. Bremsbänder sind nicht nur in der Montage und Herstellung einfach zu realisieren, sie sind auch extrem leicht, unempfindlich und wartungsfreundlich.In a preferred embodiment of the chain brake device according to the invention, the brake means comprise a brake band, which wraps around the brake drum. Brake bands are not only easy to implement in assembly and production, they are also extremely lightweight, insensitive and easy to maintain.

In einer bevorzugten Variante der erfindungsgemäßen motorbetriebenen Kettensäge nach sind die die Druckluftsteuerungsmittel als Unterbrecherventil ausgebildet. Auch hier gilt, dass die Unterbrechung der Zufuhr für die Druckluft verhindert, dass die Bremswirkung der Reibbremse gegen die Druckluft arbeitet.In a preferred variant of the motorized chainsaw according to the invention, the compressed air control means are designed as a breaker valve. Again, the interruption of the supply for the compressed air prevents the braking effect of the friction brake works against the compressed air.

Die Ausgestaltung der erfindungsgemäßen motorbetriebene Kettensäge besteht darin, dass die Druckluftsteuerungsmittel eine Richtungsumkehr der Druckluftrichtung bewirken. Hier wird die Richtung der Druckluft gewechselt, um den druckluftbetriebenen Antrieb mit einer Kraft entgegen der bisherigen Laufrichtung zu beaufschlagen. Dadurch wird eine Bremswirkung über die Richtungsumkehr bewirkt. Eine Reibungsbremse wird durch diese Maßnahme ggf erheblich unterstützt.The embodiment of the motorized chainsaw according to the invention is that the compressed air control means cause a reversal of direction of the compressed air direction. Here, the direction of the compressed air is changed in order to pressurize the compressed air-driven drive with a force against the previous direction. This causes a braking effect on the direction reversal. A friction brake is supported if necessary considerably by this measure.

In einer vorteilhaften Ausgestaltung des erfindungsgemäßen Verfahrens wird die Druckluftzufuhr unterbrochen. In dem Moment, wo die Druckluftzufuhr unterbrochen wird, wird der druckluftbetriebene Motor der Kettensäge nicht mehr angetrieben. Damit werden die Reibbremsen nicht mehr so stark beansprucht, weil sie nicht mehr gegen den Druckluftstrom arbeiten müssen. Die Unterbrechung der Druckluftzufuhr kommt einem vollständigen Ausschalten des Antriebs gleich.In an advantageous embodiment of the method according to the invention, the compressed air supply is interrupted. At the moment when the compressed air supply is interrupted, the chain saw powered by compressed air is no longer driven. Thus, the friction brakes are not stressed so much, because they no longer have to work against the compressed air flow. The interruption of the compressed air supply is equal to a complete shutdown of the drive.

Das erfindungsgenmäße Verfahren zum Abbremsen einer motorbetriebene Kettensäge ergibt sich dadurch, dass die Druckluftzufuhr umgekehrt wird. Durch diese Maßnahme wird erreicht, dass eine Reibbremse erheblich über die Bremsleistung des Antriebs unterstützt wird oder sogar eine Reibbremse entbehrlich macht.The erfindungsgenmäße method for braking a motor-driven chainsaw results from the fact that the compressed air supply is reversed. By this measure it is achieved that a friction brake is significantly supported by the braking power of the drive or even makes a friction brake unnecessary.

Ausgestaltungen der Erfindung sind Gegenstand der Unteransprüche. Ein Ausführungsbeispiel ist nachstehend unter Bezugnahme auf die beigefügten Zeichnungen näher erläutert.Embodiments of the invention are the subject of the dependent claims. An embodiment is explained below with reference to the accompanying drawings.

Kurze Beschreibung der ZeichnungenBrief description of the drawings

Fig.1Fig.1
zeigt in einer Prinzipskizze eine erfindungsgemäße druckluftbetriebene Kettensäge mit einer Kettenbremseinrichtung im Schnitt.shows a schematic diagram of an inventive compressed air-powered chainsaw with a chain brake device in section.
Fig.2Fig.2
zeigt in einer Prinzipskizze den schematischen Aufbau einer erfindungsgemäßen Kettensäge mit einer Kettenbremseinrichtung.shows a schematic diagram of the schematic structure of a chain saw according to the invention with a chain brake device.
Fig.3 33
zeigt Schematisch zwei Einstellpositionen der Reibbremse der KettenbremseinrichtungSchematically shows two adjustment positions of the friction brake of the chain brake device
Beschreibung des AusführungsbeispielsDescription of the embodiment

Figur 1 zeigt in einer Prinzipskizze eine druckluftbetriebene Kettensäge 10 mit einer Kettenbremseinrichtung 12 im Schnitt. Die druckluftbetriebene Kettensäge 10 weist ein Gehäuse 14 auf. An dem Gehäuse 14 sind ein erster Griff- und Bedienungsbereich 16 und ein zweiter 18 vorgesehen. An dem Gehäuse 14 ist auf einer Stirnseite 20 ein Schwert befestigt. Das Schwert ist in vorliegenden Figuren nicht dargestellt. Eine ebenfalls nicht dargestellte Sägekette läuft um das Schwert in bekannter Weise herum. Hierfür sind geeignete Führungsnuten vorgesehen. FIG. 1 shows a schematic diagram of a pneumatic chain saw 10 with a chain brake device 12 in section. The pneumatic chain saw 10 has a housing 14. On the housing 14, a first handle and operating area 16 and a second 18 are provided. On the housing 14, a sword is mounted on an end face 20. The sword is not shown in the present figures. A saw chain, also not shown, runs around the sword in a known manner. For this purpose, suitable guide grooves are provided.

In dem Gehäuse 14 befindet sich ein Kettenantrieb 22. Der Kettenantrieb 22 besteht aus einem aus einem Druckluftmotor 24 (siehe Fig. 2), der mit einem ebenfalls nicht dargestelltem Kettenantriebsrad gekoppelt ist. Der Druckluftmotor 24 besteht häufig aus einem Lamellenmotor. Der Lamellenmotor verfügt über ein im Wesentlichen zylindrisches Gehäuse, in dem Rotor mit einer Welle drehbar gelagert ist. An dem Rotor sind Lamellen vorgesehen. Das zylindrische Gehäuse weist wenigstens eine Eingangs- und eine Ausgangsöffnung auf. An der Welle des Rotors setzt ein Getriebe an, welches das Kettenantriebsrad antreibt. Bei Bedarf kann auf ein Getriebe verzichtet werden. Dann befindet sich das Kettenantriebsrad direkt auf der Welle des Rotors.In the housing 14 is a chain drive 22. The chain drive 22 consists of a compressed air from a motor 24 (see Fig. 2 ), which is coupled with a likewise not shown Kettenantriebsrad. The pneumatic motor 24 often consists of a vane motor. The vane motor has a substantially cylindrical housing in which the rotor is rotatably mounted with a shaft. Slats are provided on the rotor. The cylindrical housing has at least one inlet and one outlet opening. On the shaft of the rotor is a gear, which drives the Kettenantriebsrad. If necessary, can be dispensed with a transmission. Then the Kettenantriebsrad is located directly on the shaft of the rotor.

Die Druckluft wird mittels Kompressor erzeugt und über einen Druckluftschlauch an die Kettensäge 10 geleitet. Die Eingangsöffnung des Druckluftmotors 24 ist mit einem geeigneten Stutzen 25 versehen, an dem der Druckluftschlauch angeschlossen werden kann. Durch den Druckluftstrom wird der Rotor zum Antrieb in Bewegung gesetzt.The compressed air is generated by means of a compressor and passed through a compressed air hose to the chainsaw 10. The inlet opening of the compressed air motor 24 is provided with a suitable nozzle 25 to which the compressed air hose can be connected. Due to the compressed air flow, the rotor is set in motion to drive.

Über das Getriebe, welches in den Figuren nicht dargestellt ist, ist ferner eine Bremstrommel 28 mit dem Antrieb verbunden. Die Bremstrommel 28 ist Bestandteil der Kettenbremseinrichtung 12. Auch die Bremstrommel 28 dreht sich entsprechend dem Rotor des Kettenantriebs 22. Um die Bremstrommel 28 ist ein Bremsband 30 geschlungen. Bremstrommel 28 und Bremsband 30 bilden eine Reibbremse 31, welche den Kettenantrieb 22 durch Reibung abzubremsen versucht.About the transmission, which is not shown in the figures, a brake drum 28 is also connected to the drive. The brake drum 28 is part of the chain brake device 12. The brake drum 28 rotates according to the rotor of the chain drive 22. To the brake drum 28, a brake band 30 is looped. Brake drum 28 and brake band 30 form a friction brake 31, which tries to decelerate the chain drive 22 by friction.

Ein mechanischer Auslösemechanismus 32 ist an der Kettensäge 10 angeordnet. Der Auslösemechanismus 32 verfügt über eine Hebelkette 34 und einen Bremshebel 36, welcher als Handschutzbügel 38 ausgebildet ist. Die Hebelkette 34 weist ein Übertragungsglied 39 und einen Bremsbandhebel 41 auf. Der Bremshebel 36 ist über die Hebelkette 34 mit einer Zugfeder 45 vorgespannt. Die Zugfeder 45 ist dazu an dem Bremsbandhebel 41 angebracht. An einem Haken 40, der an dem Bremsbandhebel 41 der Hebelkette 34 vorgesehen ist, ist das Bremsband 30 befestigt. Der Bremsbandhebel 41 lässt sich um eine Drehachse 43 schwenken. In einer ersten Position des Bremshebels 36 ist das Bremsband 30 locker, so dass das Kettenantriebsrad und die Bremstrommel 30 frei drehen können. In einer zweiten und bremsenden Position des Bremshebels 36 wird das Bremsband zusammengezogen. Die Bremstrommel 28 wird durch Reibung mit dem Bremsband 30 abgebremst. Durch Lösen des Auslösemechanismus 32 wird die Kettenbremseinrichtung 12 von der frei laufenden ersten Position in eine bremsende zweite Position übergeführt. Diese Auslösung des Bremsvorgangs wird manuell durch Betätigung des Bremshebels 36 vorgenommen.A mechanical release mechanism 32 is disposed on the chain saw 10. The triggering mechanism 32 has a lever chain 34 and a brake lever 36, which is designed as a hand guard 38. The lever chain 34 has a transmission member 39 and a brake band lever 41. The brake lever 36 is biased by the lever chain 34 with a tension spring 45. The tension spring 45 is attached to the brake band lever 41. On a hook 40, which is provided on the brake band lever 41 of the lever chain 34, the brake band 30 is attached. The brake band lever 41 can be pivoted about an axis of rotation 43. In a first position of the brake lever 36, the brake band 30 is loose, so that the Kettenantriebsrad and the brake drum 30 can rotate freely. In a second and braking position of the brake lever 36, the brake band is contracted. The brake drum 28 is braked by friction with the brake band 30. By releasing the trigger mechanism 32, the chain brake device 12 is transferred from the free running first position to a braking second position. This release of the braking operation is performed manually by operating the brake lever 36.

In Fig. 3 werden die beiden Einstellpositionen der Reibbremse schematisch dargestellt. Wenn der Bremshebel 36 nach vorne gedrückt wird, wird das Bremsband 30 zusammengezogen und die Bremstrommel 28 durch Reibung abgebremst. Wenn der Bremshebel 36 nach hinten gezogen wird, ist das Bremsband 30 gelöst. Die Bremstrommel 28 und somit der mit der Bremstrommel 28 gekoppelte Kettenantrieb 22 können frei laufen.In Fig. 3 the two adjustment positions of the friction brake are shown schematically. When the brake lever 36 is pushed forward, the brake band 30 is contracted and the brake drum 28 is braked by friction. When the brake lever 36 is pulled back, the brake band 30 is released. The Brake drum 28 and thus coupled to the brake drum 28 chain drive 22 can run free.

Wie aus der Prinzipskizze von Fig. 2 ersichtlich wird ist der Bremshebel 36 mit einem ersten Druckluftventil 42 verbunden. Das Druckluftventil 42 ist ein Steuermittel 44, welches im vorliegenden Ausftihrungsbeispiel zwei Zustände kennt: "Geöffnet" - für den laufenden Betrieb und "abgesperrt" während des Bremsvorgangs. Das erste Druckluftventil 42 sperrt die Zufuhr der Druckluft ab, sobald der Bremshebel 36 aus der ersten in die zweite bremsende Position betätigt wird. Ein Stellhebel 46 ist dazu mit dem Druckluftventil 42 zum manuellen Auslösen mit dem Bremshebel 36 verbunden. Der Bremshebel 36 und der Stellhebel 46 bilden eine Auslösevorrichtung 48. Dadurch arbeitet Reibbremse 31, nicht gegen den Kettenantrieb 22, der sonst weiter mit dem Druckluftstrom angetrieben wird. Das Bremsverhalten wird durch das Absperren des ersten Druckluftventils 42 erheblich verkürzt.As from the schematic diagram of Fig. 2 As can be seen, the brake lever 36 is connected to a first compressed air valve 42. The compressed air valve 42 is a control means 44, which in the present Ausfüihrungsbeispiel two states knows: "open" - for ongoing operation and "locked" during the braking process. The first compressed air valve 42 shuts off the supply of compressed air as soon as the brake lever 36 is actuated from the first to the second braking position. An adjusting lever 46 is connected to the compressed air valve 42 for manual release with the brake lever 36. The brake lever 36 and the adjusting lever 46 form a triggering device 48. As a result, the friction brake 31, not against the chain drive 22, which is otherwise driven by the compressed air flow. The braking behavior is significantly reduced by the blocking of the first compressed air valve 42.

Neben dem ersten Druckluftventil 42 ist ein zweites Druckluftventil 50 vorgesehen. Dieses zweite Druckluftventil 50 dient im normalen Betrieb zum Starten und Anhalten des Kettenantriebs 22. Dieses Druckluftventil 50 ist nicht mit der Reibbremse verbunden.In addition to the first compressed air valve 42, a second compressed air valve 50 is provided. This second compressed air valve 50 is used in normal operation for starting and stopping the chain drive 22. This compressed air valve 50 is not connected to the friction brake.

Erfindungsgemäß sind die Steuermittel 44 zudem so ausgelegt, dass sie anstelle des völligen Absperrens des Druckluftstroms eine zeitweilige Richtungsumkehr bewirken. Dadurch wird der Bremsvorgang auch durch den Druckluftstrom noch zusätzlich unterstützt.According to the invention, the control means 44 are also designed so that they cause a temporary reversal of direction instead of the complete shut-off of the compressed air flow. As a result, the braking process is additionally supported by the compressed air flow.

Claims (9)

  1. A chain braking device (12) for a motor-driven chain saw (10) comprising
    a) a saw chain, which is movably guided in a chain guide of the chain saw,
    b) a compressed air driven chain drive (22) by which the saw chain is driven,
    c) a brake drum (28) connected to the chain drive (22), and
    d) triggerable brake means (30, 34, 36, 38) which are provided for braking the brake drum (28) by friction,
    e) compressed air control means (44) for controlling the flow of compressed air in the compressed air driven chain saw (10), which support the braking action of the chain saw (10) via the compressed air driven chain drive (23),
    f) a trigger device (48) for operating the compressed air control means (44),
    g) the trigger device (48) coupled with a trigger mechanism (32) for triggering the brake means (30, 34, 36, 38),
    characterized in that
    h) the compressed air control means (44) cause a inversion of the direction of the compressed air, and
    i) the trigger mechanism (32) comprises a mechanical brake lever (36), wherein the brake lever (36) is provided as a hand guard (38).
  2. A chain braking device (12) for a motor-driven chain saw (10) according to claim 1, characterized in that the compressed air control means (44) are adapted as an interrupter valve (42).
  3. A chain braking device (12) for a motor-driven chain saw (10) according to any one of claims 1 to 2, characterized in that the brake means (30, 34, 36, 45) are biased.
  4. A chain braking device (12) for a motor-driven chain saw (10) according to any one of claims 1 to 3, characterized in that the braking means (30, 34, 36, 38) comprise a brake band (30) which winds around the brake drum (28).
  5. A motorized chain saw (10), comprising
    a) a saw chain, which is movable guided in a chain guide of the chain saw (10),
    b) a chain drive (22) operated by compressed air for driving the saw chain,
    c) a brake drum (28) connected to the chain drive (22), and
    d) triggerable brake means (30, 34, 36, 38) which are provided for braking the brake drum (28) by friction,
    e) compressed air control means (44) for controlling the flow of compressed air in the compressed air driven chain saw, which control the braking action via the compressed air driven chain drive (22) for braking,
    characterized in that
    f) compressed air control means (44) cause a inversion of the direction of the compressed air.
  6. A motor-operated chain saw (10) according to claim 5, characterized in that the compressed air control means (44) are adapted as an interrupter valve (42).
  7. A method for braking a motor-driven chain saw (10) with a compressed air driven chain drive (22) for driving the saw chain, characterized in that the compressed air supply is controlled for braking, wherein the compressed air supply is reversed.
  8. A method for braking a motor-driven chain saw (10) with a compressed air driven chain drive (22) for driving the saw chain according to claim 7, characterized in that the compressed air supply is interrupted.
  9. A method for braking a motor-driven chain saw (10) with a compressed air driven chain drive (22) for driving the saw chain according to claim 7, characterized in that the compressed air supply is temporally limited for braking.
EP10189385A 2010-10-29 2010-10-29 Chain brake device for a chain saw operated by pressurised air Active EP2447022B1 (en)

Priority Applications (2)

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PL10189385T PL2447022T3 (en) 2010-10-29 2010-10-29 Chain brake device for a chain saw operated by pressurised air
EP10189385A EP2447022B1 (en) 2010-10-29 2010-10-29 Chain brake device for a chain saw operated by pressurised air

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP10189385A EP2447022B1 (en) 2010-10-29 2010-10-29 Chain brake device for a chain saw operated by pressurised air

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EP2447022B1 true EP2447022B1 (en) 2013-03-13

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DE3419152A1 (en) 1984-05-23 1985-11-28 Fa. Andreas Stihl, 7050 Waiblingen Chain-braking device
JPS6032601A (en) 1983-08-01 1985-02-19 株式会社共立 Safety brake gear for chain saw
DE9000157U1 (en) * 1990-01-09 1990-09-27 Breidenbach, Bernd, 35708 Haiger Protective device against injuries caused by running chainsaws
US20040181951A1 (en) * 2003-03-17 2004-09-23 Wittke Edward R. Chain saw safety system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US12064894B2 (en) 2020-09-04 2024-08-20 Milwaukee Electric Tool Corporation Chainsaw

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EP2447022A1 (en) 2012-05-02
PL2447022T3 (en) 2013-08-30

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