WO2012024842A1

WO2012024842A1 - Hand-held power tool

Info

Publication number: WO2012024842A1
Application number: PCT/CN2010/076409
Authority: WO
Inventors: Bo Zhen; Mohsein Wan; Haihua Chai; Chunlei Song; Tie CHEN
Original assignee: Bosch Power Tools (China) Co., Ltd.
Priority date: 2010-08-27
Filing date: 2010-08-27
Publication date: 2012-03-01
Also published as: CN103079770A; CN103079770B

Abstract

A hand-held power tool (10a; 10b), in particular a drill hammer and/or a chisel hammer, comprises a striking mechanism (12a; 12b) to produce a striking pulse along a striking axis (14a; 14b) and a drive unit (16a; 16b) to drive at least the striking mechanism (12a; 12b). Moreover, the hand-held power tool (10a; 10b) comprises a housing (18a; 18b) that surrounds at least the striking mechanism (12a; 12b) and the drive unit (16a; 16b) and comprises at least one main handle (20a; 20b) which is connected to the housing (18a; 18b) and which can be gripped by an operator. At least the bulk of the main handle (20a; 20b) is located in the housing (18a; 18b) on a first side of the striking axis (14a; 14b), and at least the bulk of the drive unit (16a; 16b) is located in the housing (18a; 18b) on a second side (22a; 22b) opposite to the first side of the striking axis (14a; 14b). Thereby, a compact structure of the hand-held power tool (10a; 10b) can advantageously be achieved, and the operator can easily handle the hand-held power tool (10a; 10b).

Description

Hand-Held Power Tool

Field of Invention

The invention relates to a hand-held power tool, in particular a drill hammer and/or a chisel hammer.

Background Art

Hand-held power tools which comprise a striking mechanism to produce a striking pulse along a striking axis and a drive unit to drive the striking mechanism are well- known. The drive unit of such hand-held power tools is supported in a housing of such hand-held power tools on a side of the striking axis facing a main handle of the handheld power tools.

Summary of the Invention

The invention relates to a hand-held power tool, in particular a drill hammer and/or a chisel hammer, that comprises a striking mechanism to produce a striking pulse along a striking axis and a drive unit to drive at least the striking mechanism. Moreover, the hand-held power tool comprises a housing that surrounds at least the striking mechanism and the drive unit and comprises at least one main handle which is connected to the housing and which can be gripped by an operator.

It is recommended that at least a bulk of said main handle is located in said housing on a first side of the striking axis and at least a bulk of the drive unit is located in the housing on a second side opposite to the first side of the striking axis. Preferably, supporting points of the drive unit are located on the side of the striking axis facing away from the main handle. The hand-held power tool according to the invention can be battery- operated and/or cable -based. In this context, the term "striking mechanism" shall define a mechanism which is provided to produce a pulse via a cooperation with at least a hammer and a piston, in particular an axial striking pulse, and/or to directly or indirectly transmit a pulse, in particular an axial striking pulse, to a tool of the hand-held power tool which is inserted into a tool holder of the hand-held power tool. The tool can be configured as a drill or a chisel. To indirectly transmit the striking pulse to the tool, the striking mechanism preferably comprises a striker that is formed by a part which is separate from the hammer. The striker directly contacts the tool to transmit the striking pulse when the striking mechanism is operated. The piston according to the invention is preferably configured as a pot-shaped piston. It is also possible to configure the piston in another shape which is considered expedient by a person skilled in the art. The striking axis preferably extends along a rotation axis of the tool holder that is driven by the drive unit via at least the striking mechanism. Furthermore, in this context a "drive unit" shall define a unit which comprises at least a motor, especially an electric motor, that has at least a rotor and a stator. The drive unit and the main handle are preferably located in an area of an interior of the housing which is cut by an axis extending perpendicular to the striking axis. In this context, "a main handle" should define a handle of the hand-held power tool which is located on a side opposite to the tool holder. Preferably, the main handle has an extension along a circumference of the main handle which is smaller than 20 cm. Thereby, a compact structure of the hand-held power tool can advantageously be achieved.

In addition, at least 50% of the drive unit, in particular 50% of the mass fraction and/or the volume fraction of the drive unit, are arranged on the second side of the striking axis opposite to the first side of the striking axis. Favourably, 80% of the mass fraction and/or the volume fraction of the drive unit are arranged on the second side of the striking axis opposite to the first side of the striking axis. Thereby, a centre of gravity of the hand-held power tool can advantageously be influenced by determining a position of the drive unit in the housing of the hand-held power tool.

Preferably, at least 100% of the drive unit, in particular 100% of the mass fraction and/or the volume fraction of the drive unit, are arranged on the second side of the striking axis opposite to the first side of the striking axis. Thereby, an advantageous arrangement of the drive unit in the housing can be achieved. Preferably, the drive unit is arranged in an area of an interior of the housing which is nearby the main handle, so that a centre of gravity is located nearby the main handle. Thereby, an operator can easily handle the hand-held power tool.

In a preferred embodiment of the hand-held power tool the drive unit is distantly located relative to the striking axis. Preferably, the drive unit is distantly located along a direction perpendicular to the striking axis so that there is a gap between the striking axis and the drive unit along the direction perpendicular to the striking axis. Thereby, an advantageous arrangement of the drive unit in an interior of the housing can be achieved.

Furthermore, the drive unit has a rotation axis which extends essentially parallel to said striking axis. In this context, the term "substantially parallel" shall define an orientation of a first direction relative to a second direction wherein the first direction has a deflec- tion relative to the second direction which is smaller than 5° and preferably smaller than 2°. Thereby, packaging space can advantageously be used. Moreover, a compact structure of the hand-held power tool can advantageously be achieved.

In addition, the striking mechanism comprises a wobble drive to convert a rotary motion of the drive unit into a reciprocating motion of a piston of the striking mechanism. The wobble drive is supported in the housing on the second side of the striking axis opposite to the first side of the striking axis. The wobble drive is embodied in a manner which is well-known to a person skilled in the art. The arrangement of the wobble drive in conjunction with the arrangement of the drive unit can have a positive impact on a tilting effect during an operation of the hand-held power tool.

In a preferred embodiment, the hand-held power tool further comprises an energy storage module to supply the drive unit, especially an electric motor of the drive unit, with energy. The energy storage module is connectable to the main handle on a side of the main handle facing away from the drive unit. Preferably, the energy storage module is integrated into the main handle. Thereby, a compact hand-held power tool decoupled from a cable for an energy supply can be achieved. Moreover, an advantageous mass distribution can be achieved, wherein a large part of the centre of gravity is located nearby the main handle.

Furthermore, at least 80% of the main handle, in particular 80% of a mass fraction and/or a volume fraction of the main handle, are located on the first side of the striking axis. Preferably, 100% of a mass fraction and/or a volume fraction of the main handle are located on the first side of the striking axis. Thereby, an advantageous mass fraction can be achieved.

Brief Description of the Drawings

Other objects, features and advantages of the present invention will become apparent from a reading of the following detailed description when taken in conjunction with the accompanying drawings wherein a particular embodiment of the invention is disclosed as an illustrative example.

Fig. 1 shows a first embodiment of a hand-held power tool according to the invention with a disassembled housing part in a schematic representation; and Fig. 2 shows an alternative embodiment of a hand-held power tool according to the invention with a disassembled housing part in a schematic representation.

Detailed Description of the Invention

Figure 1 shows a hand-held power tool 10a which comprises a striking mechanism 12a to produce a striking pulse along a striking axis 14a and a drive unit 16a to drive the striking mechanism 12a. The hand-held power tool 10a is configured as a battery- operated drill hammer 32a. Alternatively, the hand-held power tool 10a can also be configured as a chipping hammer (not shown). The drill hammer 32a comprises a housing 18a that surrounds the striking mechanism 12a and the drive unit 16a. The housing 18a has two housing parts 34a (only one is shown in Figure 1) which are connectable via fastening elements (not shown) along a plane extending through the striking axis 14a and through a rotation axis 24a of the drive unit 16a. One of the housing parts 34a is disassembled in Figure 1.

The drill hammer 32a further comprises a main handle 20a which is connected to the housing 18a and which can be gripped by an operator using the drill hammer 32a. The main handle 20a also comprises two main handle parts 36a (only one is shown in Figure 1). Each of the main handle parts 36a is formed as one piece with one of the housing parts 34a. Therefore, the main handle parts 36a are also connectable with each other via fastening elements (not shown) along the plane extending through the striking axis 14a and through the rotation axis 24a of the drive unit 16a. The main handle 20a extends along a direction facing away from the drive unit 16a. 100% of a mass fraction and/or a volume fraction of the main handle 20a are located on the first side of the striking axis 14a. Moreover, the main handle 20a comprises a point of force application which is on the striking axis 14a. Therefore, an essential part of a force generated by an operator during a use of the drill hammer 32a acts along a working direction which is parallel or coaxial to the striking axis 14a. Furthermore, the drill hammer 32a comprises a tool holder 38a to accommodate a tool (not shown). The tool holder 38a is located along a main extension direction 40a of the hand-held power tool 10a on a side 42a opposite to the main handle 20a of the drill hammer 32a. The main extension direction 40a is parallel to the striking axis 14a of the striking mechanism 12a.

The drive unit 16a of the hand-held power tool 10 is located in the housing 18a on the second side 22a of the striking axis 14a opposite to the first side of the striking axis 14a. At least 50% of the drive unit 16a are arranged on the second side 22a of the striking axis 14a opposite to the first side of the striking axis 14a. The drive unit 16a, viewed sterically, is arranged in the housing 18a above a plane which extends through the striking axis 14a and which is perpendicular to the plane along which the housing parts 34a of the housing 18a are connectable with each other.

The drive unit 16a comprises an electric motor 44a and at least one gear wheel 46a embodied as a pinion. The gear wheel 46a is formed as one piece with an armature shaft 48a of the electric motor 44a. It is also possible that the drive unit 16a comprises another motor like a pneumatic driven motor etc. to drive the striking mechanism 12a. Moreover, it is also possible that the drive unit 16a further comprises a transmission unit like, for example, a planetary gear which is arranged along a drive train between the electric motor 44a and the striking mechanism 12a.

In a preferred embodiment of the hand-held power tool 10a 100% of a mass fraction and/or a volume fraction of the drive unit 16a are arranged on the second side 22a of the striking axis 14a opposite to the first side of the striking axis 14a. The drive unit 16a is distantly located relative to the striking axis 14a. The rotation axis 24a of the electric motor 44a of the drive unit 16a extends essentially parallel to the striking axis 14a. The rotation axis 24a of the electric motor 44a is distantly located to the striking axis 14a. A distance between the rotation axis 24a and the striking axis 14a along a direction 50a perpendicular to the striking axis 14a and the rotation axis 24a is about one-third of an extension of the electric motor 44a along the direction 50a perpendicular to the striking axis 14a and the rotation axis 24a.

Furthermore, the striking mechanism 12a of the hand-held power tool 10a comprises a wobble drive 26a to convert a rotary motion of the drive unit 16a into a reciprocating motion of a piston 28a of the striking mechanism 12a. The piston 28a is embodied as a pot-shaped piston. The striking pulse along the striking axis 14a is produced in a well- known manner by the striking mechanism 12a. The wobble drive 26a is also supported in the housing 18a on the second side 22a of the striking axis 14a opposite to the first side of the striking axis 14a. At least 80% of a mass fraction and/or a volume fraction of the wobble drive 26a are located on the second side 22a of the striking axis 14a opposite to the first side of the striking axis 14a.

The striking mechanism 12a further comprises a hammer tube 52a that has a cylindrical shape. The hammer tube 52a slidably supports the piston 28a, a hammer and a striker along the striking axis 14a. A rotation axis of the hammer tube 52a is parallel or coaxial to the striking axis 14a. Therefore, on the second side 22a of the striking axis 14a opposite to the first side of the striking axis 14a the drive unit 16a and the striking mecha- nism 12a are gradually located relative to each other along the striking axis 14a. The rotation axis of the hammer tube 52a is displaced along the direction 50a perpendicular to the striking axis 14a relative to a rotation axis of the wobble drive 26a. The rotation axis of the wobble drive 26a is parallel to the striking axis 14a and to the rotation axis 24a of the electric motor 44a. Moreover, the rotation axis of the wobble drive 26a is displaced along the direction 50a perpendicular to the striking axis 14a relative to the rotation axis 24a of the electric motor 44a.

Furthermore, the hand-held power tool 10a comprises an energy storage module 30a (schematically shown in Figure 1) to supply the electric motor 44a of the drive unit 16a with energy. The energy storage module 30a is connectable to the main handle 20a on a side of the main handle 20a facing away from the drive unit 16a. The energy storage module 30a is embodied as an accumulator pack 54a. The accumulator pack 54a is connectable to the main handle 20a via a detent connection or the like. It is also possible that the accumulator pack 54a is completely insertable into the main handle 20a. The accumulator pack 54a is a balancing mass relative to the drive unit 16a so that a mass distribution of the hand-held power tool 10a is in a large part nearby the main handle 20a. An operator can easily handle the hand-held power tool 10a because a centre of gravity of the hand-held power tool 10a is nearby the main handle 20a.

Figure 2 shows an alternative embodiment of the present invention. Parts, features and functions which are essentially the same are numbered with the same reference numerals. For differentiation of the embodiments, letters a and b are added to the reference numerals. The following description is restricted to the differences between the embodiments shown and described in figure 1. With regard to the parts, the features and the functions which are unchanged, it is pointed out that the description of the embodiment of figures 1 already describes these parts, features and functions.

Figure 2 shows a hand-held power tool 10b which comprises a striking mechanism 12b to produce a striking pulse along a striking axis 14b and which comprises a drive unit 16b to drive the striking mechanism 12b. The hand-held power tool 10b comprises a housing 18b that surrounds the striking mechanism 12b and the drive unit 16b. Furthermore, the hand-held power tool 10b comprises a main handle 20b which is connected to the housing 18b and which can be gripped by an operator using the hand-held power tool 10b. A bulk of the main handle 20b is located in the housing 18b on a first side of the striking axis 14b and a bulk of the drive unit 16b is located in the housing 18b on a second side 22b opposite to the first side of the striking axis 14b. The handheld power tool 10b is embodied as a cable -based drill hammer 32b. A power cable (not shown) of the hand-held power tool 10b has to be first connected to an energy source before an operator can power the drive unit 16b of the hand-held power tool 10b.

The main handle 20b of the hand-held power tool 10b is embodied V-shaped so that the main handle 20b has a first leg 56b and a second leg 58b. The first leg 56b and the second leg 58b are connected to each other via a curved section 60b of the main handle 20b. Moreover, the first leg 56b of the main handle 20b is connected to the housing 18b in an area of the drive unit 16b and the second leg 58b is connected to the housing 18b in an area of the striking mechanism 12b.

Thus, the present invention may be practiced and/or configured otherwise than as specifically described above. Many changes, alternatives, variations, and equivalents to the various structures shown and described will be apparent to one skilled in the art. Accordingly, the present invention is not intended to be limited to the particular embodiments illustrated but is intended to cover all such alternatives, modifications, and equivalents as may be included within the spirit and broad scope of the invention as defined by the following claims. All patents, patent applications, and printed publications referred to herein are hereby incorporated by reference in their entirety.

Claims

1. A hand-held power tool, comprising:

a striking mechanism (12a; 12b) to produce a striking pulse along a striking axis (14a; 14b);

a drive unit (16a; 16b) to drive at least said striking mechanism (12a; 12b);

a housing (18a; 18b) that surrounds at least said striking mechanism (12a; 12b) and said drive unit (16a; 16b); and

at least one main handle (20a; 20b) which is connected to said housing (18a; 18b) and which can be gripped by an operator;

wherein at least a bulk of said main handle (20a; 20b) is located in said housing (18a; 18b) on a first side of said striking axis (14a; 14b) and wherein at least a bulk of said drive unit (16a; 16b) is located in said housing (18a; 18b) on a second side (22a; 22b) opposite to the first side of said striking axis (14a; 14b).

2. The hand-held power tool as defined in Claim 1, wherein at least 50% of said drive unit (16a; 16b) are arranged on said second side (22a; 22b) of said striking axis (14a; 14b) opposite to said first side of said striking axis (14a; 14b).

3. The hand-held power tool as defined in one of the preceding Claims, wherein at least 100% of said drive unit (16a; 16b) are arranged on said side (22a; 22b) of said striking axis (14a; 14b) opposite to said first side of said striking axis (14a; 14b).

4. The hand-held power tool as defined in Claim 3, wherein said drive unit (16a; 16b) is distantly located relative to said striking axis (14a; 14b).

5. The hand-held power tool as defined in one of the preceding Claims, wherein said drive unit (16a; 16b) has a rotation axis (24a; 24b) which extends essentially parallel to said striking axis (14a; 14b).

6. The hand-held power tool as defined in one of the preceding Claims, wherein said striking mechanism (12a; 12b) comprises a wobble drive (26a; 26b) to convert a rotary motion of said drive unit (16a; 16b) into a reciprocating motion of a piston (28a; 28b) of said striking mechanism (12a; 12b) and wherein said wobble drive (26a; 26b) is supported in said housing (18a; 18b) on said second side (22a; 22b) of said striking axis (14a; 14b) opposite to said first side of said striking axis (14a; 14b).

7. The hand-held power tool as defined in one of the preceding Claims, further comprising an energy storage module (30a; 30b) to supply said drive unit (16a; 16b) with energy, wherein said energy storage module (30a; 30b) is connectable to said main handle (20a; 20b) on a side of said main handle (20a; 20b) facing away from said drive unit (16a; 16b).

8. The hand-held power tool as defined in one of the preceding Claims, wherein at least 80% of said main handle (20a; 20b) are located on said first side of said striking axis (14a; 14b).