초록 ▼

A power tool with a drive motor and a drive belt guided about a drive pulley and an output pulley has a tool driven by the drive motor through the drive belt. A tensioning device is provided that changes a spacing between the drive pulley and the output pulley and has at least one tensioning positio

A power tool with a drive motor and a drive belt guided about a drive pulley and an output pulley has a tool driven by the drive motor through the drive belt. A tensioning device is provided that changes a spacing between the drive pulley and the output pulley and has at least one tensioning position and at least one release position. In the at least one tensioning position, the drive pulley and the output pulley have a first spacing relative to one another and in the at least one release position have a second spacing to one another that is smaller than the first spacing. The drive belt is an elast belt and the tensioning device, as a result of inherent tension of the elast belt, is secured in the at least one tensioning position.

대표청구항 ▼

1. A power tool comprising: a drive motor;a drive belt guided about a drive pulley and an output pulley;a tool driven by said drive motor through said drive belt;a tensioning device adapted to change a spacing between said drive pulley and said output pulley and having at least one tensioning positi

1. A power tool comprising: a drive motor;a drive belt guided about a drive pulley and an output pulley;a tool driven by said drive motor through said drive belt;a tensioning device adapted to change a spacing between said drive pulley and said output pulley and having at least one tensioning position and at least one release position, wherein said drive pulley and said output pulley in said at least one tensioning position have a first spacing relative to one another and in said at least one release position have a second spacing to one another that is smaller than said first spacing;wherein said drive belt is an elast belt and wherein said tensioning device as a result of an inherent tension of said elast belt is secured in said at least one tensioning position;wherein, for release of said tensioning device, said tensioning device is actuated against the force of said elast belt;wherein said tensioning device has a tensioning element acting on a pressure element, wherein one of said tensioning element and said pressure element is connected to a housing of the power tool and the other one of said tensioning element and said pressure element is arranged on a movable section of an extension arm of the power tool;wherein said tensioning element is an eccentrically and rotatably supported cam;wherein said tensioning element in said at least one tensioning position acts on said pressure element; andwherein said tensioning element, when moving said tensioning device from said at least one tensioning position into said at least one release position, acts on said pressure element such that said first spacing between said drive pulley and said output pulley is enlarged and said elast belt is further tensioned before said second spacing between said drive pulley and said output pulley is reached. 2. The power tool according to claim 1, wherein said tool is arranged on said extension arm. 3. The power tool according to claim 2, wherein said moveable section of said extension arm is longitudinally movably arranged relative to said housing, wherein said drive pulley is arranged on said housing and said output pulley is arranged on said movable section of said extension arm. 4. The power tool according to claim 3, further comprising a clamping device that secures said at least one section of said extension arm relative to said housing. 5. The power tool according to claim 4, wherein said clamping device comprises at least one bolt arranged in a slotted hole. 6. The power tool according to claim 1, wherein said tensioning element acts through an actuating rod on said pressure element, wherein said actuating rod has a first end connected to said pressure element and a second end connected to said tensioning element. 7. The power tool according to claim 6, wherein said first and second ends of said actuating rod are pivotably supported. 8. The power tool according to claim 6, wherein said second end of said actuating rod is arranged in said at least one tensioning position on a first side of a connecting line that connects said first end of said actuating rod and an axis of rotation of said tensioning element, and is arranged, in said at least one release position, on a second opposite side of said connecting line. 9. The power tool according to claim 1, comprising a stop for said tensioning element on which said tensioning element rests in said at least one tensioning position. 10. The power tool according to claim 9, wherein said tensioning device is arranged in a receptacle of said extension arm and wherein said stop is formed by a wall of said receptacle. 11. The power tool according to claim 1, wherein said tensioning device is arranged in a receptacle inside a belt loop of said drive belt. 12. The power tool according to claim 1, wherein said tensioning device comprises an adjusting element that is embodied as a rotatable adjusting knob. 13. The power tool according to claim 12, wherein said tensioning device comprises a tensioning element that is formed on said adjusting knob. 14. The power tool according to claim 1, wherein said elast belt in said at least one release position is loosened and can be mounted and demounted in a simple way. 15. A power tool comprising: a drive motor;a drive belt guided about a drive pulley and an output pulley;a tool driven by said drive motor through said drive belt;a tensioning device adapted to change a spacing between said drive pulley and said output pulley and having at least one tensioning position and at least one release position, wherein said drive pulley and said output pulley in said at least one tensioning position have a first spacing relative to one another and in said at least one release position have a second spacing to one another that is smaller than said first spacing;wherein said drive belt is an elast belt and wherein said tensioning device as a result of an inherent tension of said elast belt is secured in said at least one tensioning position;wherein, for release of said tensioning device, said tensioning device is actuated against the force of said elast belt;wherein said tensioning device has a tensioning element acting on a pressure element, wherein one of said tensioning element and said pressure element is connected to a housing of the power tool and the other one of said tensioning element and said pressure element is arranged on a moveable section of an extension arm of the power tool;wherein said tensioning element is an eccentrically and rotatably supported eccentric cam;wherein said eccentric cam in said at least one tensioning position acts on said pressure element and said pressure element is resting on a contact location of said eccentric cam in said at least one tensioning position, wherein said contact location has a distance relative to a pivot axis of said eccentric cam;wherein, when moving said tensioning device from said at least one tensioning position into said at least one release position, said distance of said contact location to said pivot axis initially increases and then decreases. 16. The power tool according to claim 15, wherein said tensioning device comprises a clamping device and wherein said eccentric cam is supported on a bolt of said clamping device, wherein said bolt is a fastening bolt. 17. The power tool according to claim 15, wherein said eccentric cam is supported on a bolt that is fixedly connected to said housing and is a bearing pin. 18. The power tool according to claim 15, wherein said eccentric cam has at least one recess and said pressure element rests in said recess in one position of said tensioning element. 19. The power tool according to claim 15, wherein said eccentric cam has at least one stop that delimits a rotational movability of said eccentric cam. 20. The power tool according to claim 15, wherein said eccentric cam acts through a pushrod on said pressure element, wherein said pushrod is longitudinally movably guided in a guide. 21. A power tool comprising: a drive motor;a drive belt guided about a drive pulley and an output pulley;a tool driven by said drive motor through said drive belt;a tensioning device adapted to change a spacing between said drive pulley and said output pulley and having at least one tensioning position and at least one release position, wherein said drive pulley and said output pulley in said at least one tensioning position have a first spacing relative to one another and in said at least one release position have a second spacing to one another that is smaller than said first spacing;wherein said drive belt is an elast belt and wherein said tensioning is secured in said at least one tensioning position device only by an inherent tension of said elast belt, with no spring being provided that secures said tensioning device in said at least one tensioning position;wherein, for release of said tensioning device, said tensioning device is actuated against the force of said elast belt;wherein said tensioning device has a tensioning element acting on a pressure element, wherein one of said tensioning element and said pressure element is connected to a housing of the power tool and the other one of said tensioning element and said pressure element is arranged on a movable section of an extension arm of the power tool;wherein said tensioning element in said at least one tensioning position acts on said pressure element; andwherein said tensioning element, when moving said tensioning device from said at least one tensioning position into said at least one release position, acts on said pressure element such that said first spacing between said drive pulley and said output pulley is enlarged and said elast belt is further tensioned before said second spacing between said drive pulley and said output pulley is reached.