Tool holding device for a power tool, power tool therewith

Abstract

Impact mechanism (15) with a dry-blow damping element and a recoil damping element (6, 7) which interact with a tool holder (3), wherein the tool holder (3) is mounted relative to a guide housing (5) via at least two sliding bearings (13), and wherein the dry-blow damping element and the recoil damping element (6, 7) are arranged at an axial distance from each other on the outer circumference of the tool holder (3). The dry-blow damping element (6) and / or the recoil damping element (7) is coupled to the tool holder (3) via a face-mounted or inner-circumferential toothing (8), and the same damping element (6 or 7) is coupled to the guide housing (5) via a face-mounted or outer-circumferential toothing (11). Power tool (2), in particular a rotary hammer or chisel hammer, with an impact mechanism (15) according to the invention.

Description

[0001] The invention relates to an impact mechanism for a power tool according to the preamble of claim 1. The power tool may in particular be a rotary hammer or chisel hammer. Furthermore, the invention relates to a power tool, in particular a rotary hammer or chisel hammer, with a tool holder device according to the invention. State of the art

[0002] Rotary hammers and / or demolition hammers have a percussion mechanism that typically transfers the necessary impact energy to a tool via a ram. The ram is axially movable within a tubular tool holder, into which the tool can be inserted at the other end. The ram moves back and forth between two stops within the tool holder, so that some of the kinetic energy is also transferred to the tool holder itself. This can lead to undesirable noise and / or unpleasant vibrations in the housing into which the tool holder is mounted.

[0003] From EP 4 400 265 A1, an impact mechanism for a power tool is known, which has a tubular tool holder for a tool. The tool holder is mounted in a guide housing, at the proximal end of which a coaxially rearward-positioned impact plunger is provided. Between the tool holder and the guide housing, an arrangement consisting of a dry-blow damping element and a recoil damping element is positioned, which interact with the tool holder to provide dry-blow and recoil damping. The tool holder is mounted to the guide housing via at least two sliding bearings, which are provided on the axial outer sides of the arrangement consisting of the dry-blow damping and recoil damping elements. The dry-blow damping and recoil damping elements are arranged axially apart from each other on the outer circumference of the tool holder.

[0004] Based on the aforementioned prior art, the present invention aims to improve damping by means of a modified mounting of a tool holder within a housing or housing part.

[0005] To solve the problem, the impact mechanism with the features of claim 1 is proposed. Advantageous embodiments of the invention are described in the dependent claims. Furthermore, a power tool with an impact mechanism according to the invention is described. Disclosure of the invention

[0006] A proposed impact mechanism for a power tool, in particular for a rotary hammer or chisel hammer, comprises a tubular tool holder for a tool, which is received in a guide housing and at whose proximal end a coaxially rearward-arranged impact plunger is provided, wherein an arrangement of an idle impact damping element and a recoil impact damping element is positioned between the tool holder and the guide housing, which interact with the tool holder to achieve idle impact and recoil impact damping, wherein the tool holder is mounted to the guide housing via at least two sliding bearings, which are provided on axial outer sides of the arrangement of idle impact damping element and recoil impact damping element, and wherein the idle impact damping element and the recoil impact damping element are arranged at an axial distance from each other on the outer circumference of the tool holder.

[0007] According to the invention, it is proposed that the idle impact damping element and / or the rebound impact damping element is coupled to the tool holder via a face-side or inner circumferential toothing and the same damping element is coupled to the guide housing via a face-side or outer circumferential toothing.

[0008] The toothed face creates a circumferential positive locking connection between the idle impact damping element and / or the recoil impact damping element and the tool holder, thus preventing the idle impact damping element and / or the recoil impact damping element from rotating relative to the tool holder. This eliminates the need for additional anti-rotation elements. Furthermore, connecting elements such as screws or pins for attaching the idle impact damping element and / or the recoil impact damping element to the tool holder are no longer required. As a result, the number of parts can be reduced, and weight can be saved. It is possible to configure the design so that only the idle impact damping element or only the recoil impact damping element – ​​hereinafter collectively referred to as damping elements – is coupled to the tool holder in this manner.Alternatively, it can also be provided that both the idle impact damping element and the rebound impact damping element are coupled to the tool holder.

[0009] By arranging the teeth on the end faces, the damping elements are simultaneously supported in the axial direction. Damping can thus be achieved via the damping elements in both the axial and circumferential directions.

[0010] Because the idle impact damping element and / or the recoil impact damping element have an external circumferential toothing for coupling with the guide housing, the tool holder in the guide housing is elastically mounted in both the axial and circumferential directions via the idle impact damping element and / or the recoil impact damping element. At the same time, the idle impact damping element and / or the recoil impact damping element provides anti-rotation protection, preventing the tool holder from rotating relative to the guide housing.

[0011] Preferably, the tool holder for interaction with the idle impact damping element and / or the recoil impact damping element has an annular collar with teeth, preferably teeth on both sides. The teeth on both sides of the annular collar are preferably adapted to the teeth of the idle impact damping element and / or the recoil impact damping element, so that they interlock when the two damping elements are arranged appropriately with respect to the annular collar.

[0012] The two damping elements are preferably arranged on both sides of the ring collar, so that their end-face teeth engage with one of the teeth formed on both sides of the ring collar. The axial distance between the two damping elements thus corresponds to the width of the ring collar minus the teeth formed on both sides. The ring collar also supports the two damping elements axially: the idle impact damping element in a first axial direction and the rebound impact damping element in a second axial direction opposite to the first.

[0013] In order to bring the end-face teeth of the damping elements into engagement with the teeth of the ring collar of the tool holder, the two damping elements are preferably oriented towards each other so that the end-face teeth face each other.

[0014] Advantageously, the two damping elements are identical in design, allowing the use of the same parts, which only need to be arranged in different orientations on the tool holder or tool holder body. Using identical parts reduces manufacturing costs. The correct orientation of the damping elements during assembly is ensured by the toothed ends of the damping elements. These teeth only allow for one orientation to engage with the toothed ends of the ring collar on both sides of the tool holder.

[0015] Furthermore, a power tool, in particular a rotary hammer or chisel hammer, is proposed, comprising a guide housing and an impact mechanism according to the invention. The tool holder is dampened within the guide housing in two opposing axial directions via the idle impact damping element and the recoil impact damping element. The impact mechanism according to the invention achieves improved damping, which is noticeable during operation of the power tool through reduced noise and vibration. Furthermore, the impact mechanism according to the invention reduces weight, as the number of parts is reduced by integrating the function into the idle impact damping element and / or the recoil impact damping element. The weight reduction is further enhanced by the fact that the assembly of the two damping elements preferably does not require any metallic connecting elements, such as screws or pins.

[0016] Preferably, the idle impact damping element and / or the recoil impact damping element are coupled to the housing part via an external circumferential toothing. The external circumferential toothing creates a positive locking effect in the circumferential direction, so that the tool holder is elastically mounted in the circumferential direction and is also secured against rotation relative to the guide housing.

[0017] Furthermore, the guide housing preferably has an internal circumferential toothing for coupling with the idle impact damping element and / or the recoil impact damping element. The internal circumferential toothing of the guide housing is preferably adapted to the external circumferential toothing of the idle impact damping element and / or the recoil impact damping element, so that they mesh after the tool holder is inserted into the guide housing.

[0018] In a further development of the invention, it is proposed that the idle impact damping element and the recoil impact damping element are arranged between two annular sliding bearings for axial position retention. These bearings are preloaded radially against the tool holder and the guide housing, either directly or indirectly via sealing rings. The annular sliding bearings can be mounted on the tool holder together with the damping elements and then inserted into the guide housing along with the tool holder. The radial preload of the sliding bearings serves to secure their axial position, preventing axial displacement of the sliding bearings and the damping elements during insertion. The sliding bearings thus facilitate the assembly of the power tool. At the same time, the radial preload provides a seal, which can be optimized by preloading the sliding bearings not directly, but indirectly via sealing rings in the radial direction.Advantageously, sealing rings are arranged on both sides of the sliding bearings to seal both the radial gap between the tool holder and the sliding bearing and the radial gap between the sliding bearing and the guide housing.

[0019] According to a preferred embodiment of the invention, the impact mechanism is arranged in the guide housing, wherein the impact mechanism is designed with an impact piston for acting on an impact plunger, the impact plunger being mounted axially movable in the tool holder. An impact force acting in the axial direction can be exerted on the impact plunger via the impact piston of the impact mechanism, and via the impact plunger on a tool held in the tool holder, so that the tool is moved back and forth in the axial direction. The tool can, for example, be a chisel. The impact piston, the impact plunger, and the tool are arranged coaxially for this purpose.

[0020] A preferred embodiment of the invention is described in more detail below with reference to the accompanying drawings. These show: Fig. 1 shows a section of a longitudinal section through a power tool with a percussion mechanism according to the invention, Fig. 2 shows a perspective view of the power tool. Figure 1 , Fig. 3 a perspective view of the tool holder and damping elements of the tool holder of the power tool of the Figure 1 (before assembly); and Fig. 4 a perspective view of the guide housing of the power tool of the Figure 1 . Detailed description of the drawings

[0021] The Figure 1 and 2A power tool 2 with an impact mechanism 15 according to the invention is to be removed. The impact mechanism is received in a tubular guide housing 5. The impact mechanism 15 comprises an impact piston 16 for acting on an impact plunger 17, which is axially movably received in a tubular tool holder 3 or tool holder body.

[0022] The tool 4 can be secured within the tool holder 3 in the conventional manner, so a more detailed description is omitted. The focus is instead on the mounting of the tool holder 3 within the guide housing 5.

[0023] A tool 4 can be inserted in the distal end of the tool holder 3 and is held axially displaceably within the tool holder 3. A striking plunger 17 is arranged in the tool holder 3 at a proximal end. The striking plunger 17 is axially displaceable in order to transmit an impact impulse applied to the striking plunger 17 to the tool 4.

[0024] The impact plunger 17 is guided by distal and proximal impact plunger bearings 30, 31. In a central region, the impact plunger 17 has a radial extension 32 which, during a dry strike, interacts with an impact plunger dry-strike damping element 34 on the side of the distal impact plunger bearing 30, thus damping the impact energy of the impact plunger 17. On the side of the proximal impact plunger bearing 31, an impact plunger rebound damping element 35 is arranged, which absorbs the impact energy of the impact plunger 17 during a rebound strike. This prevents the impact energy from being transmitted undamped to the structure.

[0025] The tool holder 3 forms an annular collar 9 or radial extension. On a distal side to the annular collar 9, an annular impact damping element 6 is arranged between the guide housing 5 and the tool holder 3. During an impact, in which the tool holder 4 is displaced towards the impact damping element 6, the radial extension 3 interacts with the impact damping element 6, thus damping the impact. An annular recoil damping element 7 is arranged on a proximal side of the annular collar 9. During a recoil impact, the annular collar 9 is displaced towards the recoil damping element 7, thus damping the impact.

[0026] As particularly in Figure 3As can be seen, both the idle impact damping element 6 and the recoil impact damping element 7 each have a face toothing 8 and an outer circumferential toothing 11. The two damping elements 6, 7 are oriented relative to each other such that the face toothing 8s are facing each other. The ring collar 9 of the tool holder 3 extends between the two damping elements 6, 7 and has toothing 10s on both sides. The face toothing 8s of the two damping elements 6, 7 engage with these toothing 10s. The outer circumferential toothing 11s of the two damping elements 6, 7 engage with toothing 12s formed on the inner circumferential side of the guide housing 5 (see Figure 4 ).

[0027] The power tool 2 can be assembled as follows: First, the two damping elements 6, 7 are slid onto the tool holder 3, with the idle impact damping element 6 being placed on one side and the recoil impact damping element 7 on the other. In the final position, the end teeth 8 of the damping elements 6, 7 engage with the teeth 10 formed on both sides of the ring collar 9. To secure the damping elements 6, 7 on the tool holder 3, annular sliding bearings 13 are then placed on the tool holder 3 and pushed up against the damping elements 6, 7 (see Figure 1The plain bearings 13 have sealing rings 14 on their inner and outer circumferences, the inner sealing rings 14 bearing against the tool holder 3 under a radial preload after the plain bearings 13 are mounted on the tool holder 3. The pre-assembled unit can then be inserted into the guide housing 5, with the outer sealing rings 14 of the plain bearings 13 being radially preloaded against the guide housing 5.

[0028] The tool holder 3 is elastically mounted in the guide housing 5 via the two damping elements 6, 7, both axially and circumferentially. Thus, improved damping is achieved during operation of the power tool 2 via the two damping elements 6, 7. Reference symbol list

[0029] 2 Power tool 3 Tool holder 4 Tool 5 Guide housing 6 Idle impact damping element 7 Rebound impact damping element 8 Toothing 9 Ring collar 10 Toothing 11 Toothing 12 Toothing 13 Plain bearing 14 Sealing ring 15 Impact mechanism 16 Impact piston 17 Impact plunger 30 Distal impact plunger bearing 31 Proximal impact plunger bearing 32 Radial extension 34 Impact plunger idle impact damping element 35 Impact plunger rebound impact damping element

Claims

1. Impact mechanism (15) for a power tool (2), in particular for a rotary hammer or chisel hammer, comprising a tubular tool holder (3) for a tool (4), which is received in a guide housing (5) and at the proximal end of which a coaxially rearward-arranged impact plunger (17) is provided, wherein an arrangement of a dry-blow damping element and a recoil damping element (6, 7) is positioned between the tool holder (3) and the guide housing (5), which interact with the tool holder (3) to achieve dry-blow and recoil damping, wherein the tool holder (3) is mounted to the guide housing (2) via at least two sliding bearings (13a, 13b), which are provided on axial outer sides of the arrangement of dry-blow damping and recoil damping elements (6, 7), and wherein the dry-blow damping and recoil damping elements (6, 7)7) are arranged at an axial distance from each other on the outer circumference of the tool holder (3), , characterized by the fact that the idle impact damping element (6) and / or the rebound impact damping element (7) is coupled to the tool holder (3) via a face-side or inner circumferential toothing (8) and the same damping element (6 or 7) is coupled to the guide housing (5) via a face-side or outer circumferential toothing (11).

2. Percussion mechanism according to claim 1, characterized by the fact that the tool holder (3) for interaction with the idle impact damping element (6) and / or the recoil impact damping element (7) has a ring collar (9) with a toothing (10), preferably a toothing on both sides (10).

3. Percussion mechanism according to claim 1 or 2, characterized by the fact that the idle impact damping element (6) and the rebound impact damping element (7) have mutually facing end teeth (8).

4. Percussion mechanism according to one of the preceding claims, characterized by the fact that the idle impact damping element (6) and the rebound impact damping element (7) are of identical construction.

5. Power tool (2), in particular a rotary hammer or chisel hammer, with a guide housing (5) and a percussion mechanism (15) according to one of the preceding claims, wherein the tool holder (3) is dampened within the guide housing (5) via the idle impact damping element (6) and the rebound impact damping element (7) in two opposite axial directions.

6. Power tool (2) according to claim 5, characterized by the fact that the idle shock damping element (6) and / or the rebound shock damping element (7) is / are coupled to the guide housing (5) via an outer circumferential toothing (11).

7. Power tool (2) according to claim 5 or 6, characterized by the fact that the guide housing (5) has an internal circumferential toothing (12) for coupling with the idle shock damping element (6) and / or the rebound shock damping element (7).

8. Power tool (2) according to one of claims 5 to 7, characterized by the fact that the idle impact damping element (6) and the rebound impact damping element (7) are arranged for axial position securing between two annular sliding bearings (13), which are preloaded directly or indirectly via sealing rings (14) in a radial direction against the tool holder (3) and the guide housing (5).

9. Power tool (2) according to one of claims 5 to 8, characterized by the fact that the impact mechanism (15) is arranged in the guide housing (5), wherein the impact mechanism (15) is designed with an impact piston (16) for interaction with an impact plunger (17), wherein the impact plunger (17) is axially movable in the tool holder (3).

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