A power tool is disclosed. The power tool has a striker, which is guided along an axis in a guide tube. A pneumatic chamber has a volume which varies with a movement of the striker. The pneumatic chamber is closed by the striker, the guide tube and a valve device. The valve device has in a flow chan
A power tool is disclosed. The power tool has a striker, which is guided along an axis in a guide tube. A pneumatic chamber has a volume which varies with a movement of the striker. The pneumatic chamber is closed by the striker, the guide tube and a valve device. The valve device has in a flow channel a sealing element that is moveable between two positions in a bearing along the axis. The flow channel has a first cross-sectional area in a first of the two positions of the sealing element adjacent to a first mating surface of the bearing, and the flow channel has a second cross-sectional area in a second of the two positions of the sealing element adjacent to second mating surface of the bearing offset from the first mating surface along the axis. The second cross-sectional area is greater than the first cross-sectional area.
대표청구항▼
1. A power tool, comprising: a striker;a guide tube in which the striker is guided along an axis; anda pneumatic chamber which is closed by the striker, the guide tube, and a valve device, wherein a volume of the pneumatic chamber is variable based on a movement of the striker along the axis;wherein
1. A power tool, comprising: a striker;a guide tube in which the striker is guided along an axis; anda pneumatic chamber which is closed by the striker, the guide tube, and a valve device, wherein a volume of the pneumatic chamber is variable based on a movement of the striker along the axis;wherein, in a flow channel between the striker and the guide tube, the valve device has a sealing element that is moveable between a first position and a second position in a bearing along the axis;wherein the flow channel has a first cross-sectional area in the first position adjacent to a first mating surface of the bearing, wherein the flow channel has a second cross-sectional area in the second position adjacent to a second mating surface of the bearing offset from the first mating surface along the axis, and wherein the second cross-sectional area is greater than the first cross-sectional area;wherein the bearing is formed by a groove in the striker or a groove in the guide tube and wherein the sealing element is axially moveable in the groove between the first mating surface formed by a first groove wall and the second mating surface formed by a second groove wall. 2. The power tool according to claim 1, wherein the flow channel runs between the first mating surface of the bearing and a first mating surface of the sealing element assigned to the first mating surface of the bearing and between the second mating surface of the bearing and a second mating surface of the sealing element assigned to the second mating surface of the bearing. 3. The power tool according to claim 1, wherein the second mating surface of the bearing and/or a mating surface of the sealing element assigned to the second mating surface of the bearing have narrow channels running radially perpendicularly to the axis at least in part. 4. The power tool according to claim 1, wherein the groove and the sealing element run annularly around the axis and, in the first position, the sealing element touches the guide tube and the striker along a closed line around the axis. 5. The power tool according to claim 1, wherein the first groove wall is inclined with respect to the axis by less than 60 degrees and the second groove wall is inclined with respect to the axis by at least 80 degrees. 6. The power tool according to claim 1, wherein the striker has a prismatic first section and a prismatic second section with a larger cross-sectional area as compared to the first section and wherein the valve device is arranged on the second section of the striker. 7. The power tool according to claim 1, wherein a seal between the striker and the guide tube and offset from the valve device is provided along the axis, wherein the valve device and the seal are arranged at different distances from the axis. 8. The power tool according to claim 1, wherein the first cross-sectional area of the flow channel is a maximum of one hundredth of the second cross-sectional area of the flow channel. 9. The power tool according to claim 1, further comprising a throttle which connects the pneumatic chamber with an air reservoir, wherein a cross-sectional area of the throttle corresponds to a maximum of one hundredth of the second cross-sectional area. 10. The power tool according to claim 1, further comprising a throttle which connects the pneumatic chamber with an air reservoir, wherein an effective cross-sectional area of the pneumatic chamber is greater than a hundred times a cross-sectional area of the throttle. 11. The power tool according to claim 1, wherein an effective cross-sectional area of the pneumatic chamber is greater than a hundred times the first cross-sectional area. 12. The power tool according to claim 11, wherein the first mating surface of the bearing and/or a mating surface of the sealing element assigned to the first mating surface of the bearing has narrow channels running radially perpendicularly to the axis at least in part, and a total of their cross-sectional area is less than one hundredth of the effective cross-sectional area of the pneumatic chamber. 13. The power tool according to claim 1, further comprising a pneumatic spring defined between an exciter piston and an impacting piston, wherein the impacting piston is contactable on the striker.
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이 특허에 인용된 특허 (8)
Shinma Yasutoshi,JPX, Hammer drill with an idling strike prevention mechanism.
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