Hand-Held Power Tool, Tool and Hand-Held Power Tool System Having a Designated Ratio of Rotational Speed to Impact Frequency

Abstract

A hand-held power tool includes a tool fitting, an impact mechanism, and a rotary drive. The hand-held power tool is configured to rotate a tool held in the tool fitting with a rotational speed about a longitudinal axis of the tool and to drive the tool with an impact movement along the longitudinal axis at an impact frequency f. A ratio of the rotational speed to the impact frequency f at least at a working point of the hand-held power tool is at most 5.0 rpm/Hz or at least at the working point of the hand-held power tool the rotational speed is at most (0.2*(f/Hz-22){circumflex over ( )}2+80) rpm for impact frequencies f in a range from 20 to 60 Hz.

Claims

1.-12. (canceled)

13. A hand-held power tool (12), comprising: a tool fitting (16); an impact mechanism (32); and a rotary drive (34); wherein the hand-held power tool (12) is configured to rotate a tool (18) held in the tool fitting (16) with a rotational speed (n) about a longitudinal axis (L) of the tool (18) and to drive the tool (18) with an impact movement along the longitudinal axis (L) at an impact frequency (f) and wherein the impact mechanism (32) is a direct electromechanical, or an electropneumatic, or an electromagnetic impact mechanism; wherein a ratio of the rotational speed (n) to the impact frequency (f) at least at a working point of the hand-held power tool (12) is at most 5.0 rpm/Hz; or wherein at least at the working point of the hand-held power tool (12), the rotational speed (n) is at most (0.2*(f/Hz-22){circumflex over ( )}2+80) rpm for impact frequencies (f) in a range from 20 to 60 Hz.

14. The hand-held power tool (12) as claimed claim 13, wherein the hand-held power tool (12) is a hammer drill.

15. The hand-held power tool (12) as claimed in claim 13, wherein the ratio of the rotational speed (n) to the impact frequency (f) at least at the working point of the hand-held power tool (12) is at most 4.0 rpm/Hz.

16. The hand-held power tool (12) as claimed in claim 13, further comprising at most one drive unit for driving the impact mechanism (32) and the rotary drive (34).

17. The hand-held power tool (12) as claimed in claim 13, further comprising a tool recognition device, wherein a type of tool (18) used in the tool fitting (16) is identifiable by the tool recognition device.

18. The hand-held power tool (12) as claimed in claim 13, wherein the hand-held power tool (12) is configured such that a type of the tool (18) is settable by a user of the hand-held power tool (12).

19. The hand-held power tool (12) as claimed in claim 13, wherein the hand-held power tool (12) has a multi-stage transmission.

20. The hand-held power tool (12) as claimed in claim 13, further comprising a pneumatic or an electropneumatic cuttings conveying device (28).

21. The hand-held power tool (12) as claimed in claim 13, wherein the hand-held power tool (12) is a portable device.

22. The hand-held power tool (12) as claimed in claim 13, wherein the hand-held power tool (12) is operatable cordlessly.

23. The hand-held power tool (12) as claimed in claim 22, wherein the hand-held power tool (12) has a lithium-containing battery.

24. The hand-held power tool (12) as claimed in claim 13, further comprising an overrunning clutch or a gate-type transmission or a circular thrust transmission.

25. A tool (18) for the hand-held power tool (12) as claimed in claim 13, comprising: a tool tip (24); a tool shaft (20); and a shank (22), wherein the tool (18) is holdable in the tool fitting (16) of the hand-held power tool (12) by the shank (22); wherein a material transport channel (26) is formed at least along the tool shaft (20) and wherein the material transport channel (26) has a minimum cross-sectional area of 19 mm.sup.2 or at least 6% of a cross-sectional area of a borehole that is producible by the tool (18).

26. The tool (18) as claimed in claim 25, wherein the tool (18) is a suction drill.

27. A hand-held power tool system (10), comprising: the hand-held power tool (12) as claimed in claim 13; and the tool (18) as claimed in claim 25.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0043] The FIGURE shows a hand-held power tool system of the present invention.

DETAILED DESCRIPTION OF THE DRAWING

[0044] A hand-held power tool system 10 has a hand-held power tool 12. The hand-held power tool 12 can be operated cordlessly. For this purpose, it has a rechargeable battery 14. It is in the form of a portable device.

[0045] It also has a tool fitting 16.

[0046] A tool 18 is received in the tool fitting. For this purpose, the tool 18 has a tool shaft 20, at one end of which a shank 22 is formed and at the other end of which a tool tip 24 is formed.

[0047] The tool 18 is in the form of a hollow drill and in particular a suction drill. For this purpose, it has a material transport channel 26, which runs inside the tool shaft 20 and is shown schematically in the FIGURE, via which cuttings extracted from the vicinity of the tool tip 24 can be conveyed to a cuttings conveying device 28.

[0048] The material transport channel 26 has a cross-sectional area of 15% of the cross section of a borehole to be created by the tool 18.

[0049] Furthermore, the hand-held power tool 12 has an operating mode selector switch 30 for switching between different operating modes, in particular for switching between a pure drilling mode, a pure chiseling mode and a hammer drill mode. In the position shown of the operating mode selector switch 30, the hammer drill mode is selected. The hand-held power tool 12 can be set in motion by means of an actuating lever 31 and, in particular, operated at a working point with a device-related highest possible rotational speed.

[0050] The hand-held power tool 12 also has an electropneumatic impact mechanism 32 and a rotary drive 34. The impact mechanism 32 and the rotary drive 34 are driven by a common drive unit 36, an electric motor. The hand-held power tool 12 is configured to rotate the tool 18 held in the tool fitting 16 at a rotational speed n about a longitudinal axis L of the tool 18 and to drive the tool with an impact movement along the longitudinal axis L at an impact frequency f.

[0051] In this exemplary embodiment, the ratio of the rotational speed n to the impact frequency f at the working point is 4.0 rpm/Hz.

[0052] In alternative exemplary embodiments A2, A3, A4, A5 and A6, which can be constructed in principle, in particular structurally identically, to the exemplary embodiment described above, this ratio depends on the impact frequency f at the respective working point, in these exemplary embodiments with impact frequencies f in the range from 20 to 60 Hz, as can be seen from Table 1 below. However, the rotational speed n does not exceed (0.2*(f/Hz-22){circumflex over ( )}2+80) rpm.

TABLE-US-00001 TABLE 1 Impact Rotational Ratio Rotational speed frequency f at speed n at n to impact frequency Exemplary the working the working f at the working embodiment point (Hz) point (rpm) point (rpm/Hz) A2 20 80 4 A3 30 90 3 A4 40 120 3 A5 50 200 4 A6 60 300 5

[0053] It can be seen that at particularly low impact frequencies f, the ratio is slightly increased. In this case, even at low impact frequencies f, this enables a rock that is to be processed to be crushed evenly.

[0054] A particularly energy-saving operation arises at medium impact frequencies f.

[0055] By contrast, in the range of high crushing capacities, that is to say at higher impact frequencies f, the ratio increases again.

[0056] In order to be able to set these different ratios, the hand-held power tool 12 has a multi-stage transmission (not shown in FIG. 1). The transmission can, for example, have an overrunning clutch, a gate-type transmission or a circular thrust transmission in accordance with the European patent applications mentioned at the beginning and incorporated by reference.