GB2309660A

GB2309660A - Powered hand tool with dust extraction

Info

Publication number: GB2309660A
Application number: GB9701503A
Authority: GB
Inventors: Gutastr Reibetanz; Otto Baumann; Rolf Mueller; Heinz Neubert
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1996-02-01
Filing date: 1997-01-24
Publication date: 1997-08-06
Anticipated expiration: 2017-01-24
Also published as: GB2309660B; JPH09207013A; DE19603528B4; CH691849A5; GB9701503D0; DE19603528A1

Description

1 Powered hand tool

Prior Art

2309660 The invention is based on a powered hand tool accordmig to the precharacterising clause of claim 1. A powered hand tool constructed as a hammer drill is already known (DE-A-42 06 383), which is provided with a device for extracting drill cuttings arising during drilling or hammering. Said hammer drill is equipped with an extraction fan for conveying the drill cuttings away from the point of drilling via a suction bell and an extraction hose into a collecting bag. The suction bell is attached by a telescopic arm to an auxiliary handle on the hammer drill. For use with drilling tools the suction bell is provided with spiral dust conveyors.

An extraction device for a hammer drill is known from DE-A-29 18 629, which removes dust by suction in drilling tools with integral extraction channel. A suction head mounted rotatably with respect to a hammer drill tool holder forms a suction chamber, into which opens the extraction channel of the extraction tool. The suction head is provided with a connecting branch for connection to an extraction hose leading to the extraction fan. The suction head is arranged axially behind the tool holder, whereby dust may penetrate both the tool holder and the drive portion of the hammer drill. This results in a reduction in the efficiency of impact mission. Moreover, arrangement of the hose on one side of the suction head causes one-sided loading of the suction head, such that the latter is drawn into a slightly michned position and then wears one-sidedly. Supplementary air is then sucked into the sealing gap which opens at the side, said supplementary air reducmg the working air stream in the drilling tool.

Advantages of the Invention 2 The powered hand tool according to the mivention comprising the characterising features of claim 1 has the advantage over the above that contamination of the drive portion is avoided. Furthermore, integration into the powered hand tool of the extraction chamber with extraction channel prevents the occurrence of onesided loading, such that a constantly good extraction effect may be achieved. Moreover, damage to the known free-lying extraction hose and/or obstructions caused by such a hose during working are avoided.

The measures disclosed in the dependent claims permit advantageous modifications of and improvements to the powered hand tool according to the invention.

Drawings Two exemplary embodiments of the invention are shown in the drawings and described M" more detail in the following description. Figure 1 is a view of a powered hand tool constructed as a hammer drill, Figure 2 shows a section through part of the hammer drill at the tool end, Figure 3 shows a partial section through the hammer drill, Figure 4 shows a crosssection through the hammer drill with extraction duct according to a first exemplary embodiment and Figure 5 shows a cross-section through the hammer drill with extraction duct according to a second exemplary embodiment.

Description of the Exemplary Embodiments

In Figure 1 a hammer drill 10 is shown as an example of a powered hand tool, integral with the housing of which is formed an extraction fan 12. The hammer 3 drill 10 comprises a tool holder 13, into which a tool 14 may be inserted for drilling, percussive drilling or chiselling.

The hammer drill 10 is provided with an extraction device 18, which serves to convey drill cuttings away from the point of operation through the tool 14. an extraction duct 19 and the extraction fan 12 into a filtering collecting bag 20. For this purpose, the tool 14 is provided with a longitudinal bore 15, which passes through the tool 14 from its drill tip 14a.

Figure 2 is a sectional view of the tool holder 13. A rotationally drivable guide tube 22 in the hammer drill 10 comprises a receiving opening 23 for the insertion end 26, provided with longitudinal grooves 24, 25, of the tool 14. In a known way the longitudinal grooves 24, 25 aid the rotational drive and axial mounting of the tool 14 in the tool holder 13. A locking ball 28 is seated in a radial opening 29 in the guide tube 22 and is pressed radially into the axially closed longitudinal groove 24 in the insertion end 26 by a ring 30. The ring 30 is connected with an actuating sleeve 3 1, which is axially displaceable with respect to the guide tube 22. One end of a spring 32 rests against the guide tube 22 and pushes the actuating sleeve 31 and the ring 30 axially forwards, such that the actuating sleeve 31 rests against a stop ring 33, which sits in a groove 34 in the guide tube 22. Between the spring 3 32 and the ring 30 there is arranged an annular disk 36, which retreats axially against the force of the spring 32 when the tool 14 is inserted into the receivmig opening 23 and then enables radial disengagement of the locking ball 28 without axial actuation of the actuating sleeve 3 1. To remove the tool 14, the actuating sleeve 31 is pushed back manually, thereby radially releasing the locking ball 28.

The actuating sleeve 31 is provided at the front with a projection 37, in which is held an extraction housing 39 forming a suction chamber 38, such that the suction chamber is formed at least partially by the actuating sleeve 3 1. In the region of the suction chamber 38 the tool 14 inserted into the tool holder 13 forms a shoulder 40 with enlarged cross-section, 'm the centre of which there is disposed a transverse hole 41. Together with the longitudinal hole 15 in the tool 14 the transverse hole 41 forms an extraction channel which opens into the suction charnber 38. The suction chamber 38 is mounted axially forward of the tool holder 13 and is sealed with respect to the tool 14 at sealing points 26, 27. The extraction duct 19 extends from the suction chamber 38 to the extraction fan 12 (Figure 1). The extraction duct 16 is partially integral with the housing 11 of the hammer drill 10 (see also Figures 4 and 5).

Figure 3 is a partially sectional view of the extraction duct 19 of the hammer drill 10, by means of which the suction chamber 38 is connected with the extraction fan 12. The extraction duct 19 is composed of a connection piece 19a firmly connected with the actuating sleeve 31 and a duct portion 19b firmly connected with the housing 11 of the hammer drill 10. In the area where it joins the duct portion 19b the connection piece 19a is axially displaceable with respect to said duct portion 19b, so that axial mobility of the actuating sleeve 31 is ensured.

The duct portion 19b of the extraction duct 19 enters the radial extraction fan 12, of which a fan wheel 45 is shown in Figure 3, on the vacuum side.

Figures 4 and 5 show different exemplary embodiments of the path of the duct portion 19b to the fan 12. In the exemplary embodiment according to Figure 4 the duct portion 19b is fiffly integral with the housing 11 of the hammer 10. The wall of the duct portion 19b is formed of wearresistant material 46 inserted into the housing 11.

In Figure 5 the duct portion 19b is accommodated in a retaining groove 47, open on one side, in the housing 11 of the hammer 10. The duct portion 19b may be inserted laterally or in the longitudinal direction into the groove 47 in the housmig 11.

The invention is not restricted to the exemplary embodiments shown. Thus, the fan 12 may also be arranged at other points on the hammer drill 10. In particular, the extraction fan 12 may also be attached to the housing 11. The extraction fan 12 is advantageously arranged between the drive and gearing of the powered hand tool 10 and driven by the drive motor of the powered hand tool 10.

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Claims

1. A powered hand tool for drilling, percussive drilling and/or chiselling, especiafly a hammer drill, comprising a tool holder (13) for insertion of an extraction tool (14) provided with an extraction channel (15, 4 1), and flu-ther comprising an extraction device (18) with a suction chamber (38) into which the extraction channel (15, 41) opens when the tool (14) is inserted, characterised in that the suction chamber (38) is formed, at least partially, of a housing part (3 1) of the powered hand tool (10), especially an actuating and/or protective sleeve on the tool holder ( 13).

2. A powered hand tool according to claim 1, characterised in that, in the case of extraction tools (14) known per se with an extraction opening (41) arranged forward of the insertion end (26), the suction chamber (3 8) is mounted axially forward of the tool holder (13).

3. A powered hand tool according to claim 1 or claim 2, characteni sed in that the suction chamber (38) is connected with an extraction fan (12) via an extraction duct (19).

4. A powered hand tool according to claim 3, characterised 'm that the extraction fan (12) is integral with the powered hand tool (10) or is attached thereto.

5. A powered hand tool according to claim 3 or claim 4, characterised in that the extraction duct (19) is formed of a connection piece (19a) connected with the suction chamber (3 8) and a duct portion (1 9b) opening into the extraction fan (12).

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6. A powered hand tool according to claim 5, characterised in that the connection piece (1 9a) and the duct portion ( 1 9b) engage in each other so as to be axially displaceable with respect to each other.

7. A powered hand tool according to claim 5 or claim 6, characterised in that the duct portion (19b) extends in the housing (11) of the powered hand tool (10).

8. A powered hand tool according to claim 5 or claim 6, characterised in that the duct portion (19b) is formed on or attached to the housing (11).

9. Any of the powered hand tools substantially as herein described with reference to the accompanying drawings.