Machine tool having a bearing rocker

Abstract

The invention relates to a machine tool 1, in particular a hammer drill or chisel hammer, having a housing 5 which has a rear grip region 7, an assembly 9 which comprises a percussion mechanism device 11 and a drive device 13, the assembly being provided at least partly within the housing and mounted movably with respect to the housing, and the percussion mechanism device having a percussion axis 19 which defines a longitudinal direction Z, and a bearing by means of which the assembly is mounted on the housing so as to be movable in the longitudinal direction, the bearing having a rocker 50, one side of which is hinged to the assembly such that the assembly can be pivoted about a transverse direction X running perpendicularly to the longitudinal direction and the other side of which is hinged to the housing pivotally about the transverse direction.

Description

[0001] - 1 - 2023PF00247

[0002] Hilti Aktiengesellschaft in Schaan

[0003] Principality of Liechtenstein

[0004] Machine tool with bearing arm

[0005] The invention relates to a machine tool according to the preamble of claim 1, in particular a rotary hammer or chisel hammer. Such a machine tool is equipped with a housing having a rear handle area, with an assembly comprising an impact mechanism and a drive mechanism, wherein the assembly is at least partially arranged within the housing and is movably arranged relative to the housing, wherein the impact mechanism has an impact axis defining a longitudinal direction, and with a bearing by means of which the assembly is movably mounted on the housing in the longitudinal direction.

[0006] EP4331774 A1 describes a machine tool, in particular a rotary hammer or chisel hammer, with a housing having a grip area and an assembly comprising a percussion mechanism and a drive mechanism, wherein the assembly is substantially arranged inside the housing and is movably arranged relative to the housing.

[0007] The object of the invention is to provide a machine tool that has particularly good vibration decoupling properties with particularly low manufacturing and maintenance costs.

[0008] The problem is solved according to the invention by a machine tool having the features of claim 1. Preferred embodiments are specified in the dependent claims.

[0009] A machine tool according to the invention is characterized in that the bearing has a rocker arm to which, on the one hand, the assembly is pivotably connected about a transverse direction perpendicular to the longitudinal direction, and which, on the other hand, is pivotally connected about the transverse direction to the housing. Accordingly, the assembly is mounted on the housing via a rocker arm, the rocker arm being pivotally connected to both the assembly and the housing at different positions. The pivot axes of these two pivot connections run parallel to each other and in the transverse direction X. The connection to the assembly can be a direct connection, while the connection to the housing can be an indirect connection, for example, via a bearing fork.

[0010] Such a bearing arrangement can be advantageous in several respects. For example, in contrast to designs with a linear guide, the effort required for sealing against drilling dust can be significantly reduced. Furthermore, decoupling the bearing from the forces acting on a side handle can be achieved in a particularly simple manner. Especially if the linkage of the assembly to the rocker arm is located at or at least near the assembly's center of gravity, a particularly favorable load-bearing capacity can also be achieved very easily, and decoupling elements for vibration isolation of the assembly from the housing can be designed particularly simply and cost-effectively.

[0011] A particular advantage is that the swing arm is made of a plastic material. This allows for a particularly simple and advantageously flexible design that can preferably also accommodate three-dimensional movements.

[0012] A particularly advantageous embodiment of the invention lies in the fact that the rocker arm is designed in a fork-like form with a first fork arm and a second fork arm, wherein the assembly, in particular an inner housing of the assembly, is pivotably connected to both the first and the second fork arm in a transverse direction. In particular, the assembly, and especially its inner housing, is coaxially connected to both fork arms. Specifically, the assembly, preferably its impact mechanism, is encompassed by the two fork arms and / or the assembly, and in particular its impact mechanism, extends between the two fork arms. The design with two fork arms allows for a structurally simple and at the same time reliable mounting.

[0013] Preferably, a first bearing journal is arranged on the first fork arm, projecting into the assembly, particularly into the inner housing, and / or a second bearing journal is arranged on the second fork arm, projecting into the assembly, particularly into the inner housing. This allows for a particularly robust bearing arrangement in a particularly simple manner. The bearing journals are preferably integrally mounted on the respective fork arm.

[0014] A further preferred embodiment of the invention consists in the first fork arm and / or the second fork arm bearing against the housing, directly or indirectly via at least one intermediate piece, in a sliding manner, particularly in the longitudinal direction Z. This allows for a particularly simple implementation of lateral guidance, which can further improve operation. The housing can have ribs where the respective fork arm bears against it, which can improve the sliding behavior. In particular, it can be provided that a first sliding piece made of metal is arranged on the first fork arm for sliding contact with the housing, and / or that a second sliding piece made of metal is arranged on the second fork arm for sliding contact with the housing. This can further improve the sliding behavior.

[0015] In particular, the first sliding piece can be a sheet metal part, and / or the second sliding piece can be a sheet metal part, which can be advantageous in terms of manufacturing effort.

[0016] It is particularly advantageous for the first bearing journal to be surrounded by a first O-ring, which presses the first fork arm away from the assembly and against the housing, and / or for the second bearing journal to be surrounded by a second O-ring, which presses the second fork arm away from the assembly and against the housing. These preload-generating O-rings allow for a decoupled lateral guide to be achieved in a particularly simple manufacturing process. The O-rings can, in particular, be made of an elastomer.

[0017] For a particularly simple design, a bearing fork can be arranged on the housing, to which the rocker arm is pivotally attached. The bearing fork can be formed integrally with the housing shells or a housing cup, but is advantageously a separate component. Preferably, the bearing fork can be a double fork.

[0018] In particular, the bearing fork can be designed to encompass the swingarm. This allows for a particularly compact joint connection between the bearing fork and the swingarm.

[0019] The housing can have a side handle mounting area that can be encircled by the clamping band of a side handle, with the impact axis passing through the side handle mounting area. In particular, the assembly can be spaced apart from the housing in the side handle mounting area. This reliably decouples the stresses generated by the clamping band from the assembly and / or ensures three-dimensional movement of the assembly at the side handle mounting area.

[0020] Another preferred embodiment of the invention consists in a stiffening sleeve being arranged on the housing, which stiffens the housing in the side-handle mounting area. This allows the resilience of the machine tool to be further improved in a particularly simple manner. The stiffening sleeve can, for example, be made of a metal material, especially steel, which can also be coated. The stiffening sleeve is arranged in the side-handle mounting area. The stiffening sleeve does not need to perform a bearing function for the assembly.

[0021] The invention is explained in more detail below with reference to preferred embodiments, which are shown schematically in the accompanying figures. Individual features of the embodiments described below can, in principle, be implemented individually or in any combination within the scope of the invention. The figures schematically show:

[0022] Fig. 1 shows a highly schematic side sectional view of a first embodiment of a machine tool in the machine tool's rest position;

[0023] Fig. 2 shows a partially transparent detail view of the machine tool from Figure 1 in perspective view;

[0024] Fig. 3 is a perspective view of the bearing fork of the machine tool from Figure 2;

[0025] Fig. 4 shows a cross-sectional view of the machine tool from Figure 2 at the bearing fork;

[0026] Fig. 5 shows a longitudinal section view of the machine tool from Figure 2 in the front area of ​​the machine tool.

[0027] The figures show a first embodiment of a machine tool 1, which in this case is designed as a rotary hammer or combination hammer, but in an alternative embodiment could also be designed, for example, as a chisel hammer or the like. The machine tool 1 is designed in this case as a cordless machine tool with a battery 3, but in an alternative embodiment it can also be designed for mains operation.

[0028] The machine tool 1 is designed here in an angled configuration and has a housing 5 with a D-shaped rear grip area 7. The housing 5, which can be made of one or more parts, is fixedly connected to the user-accessible grip area 7. In this case, the housing 5 is divided longitudinally Z and constructed in a so-called cup-shaped design. Alternatively, the housing 5 can also have two housing halves that can be joined together in the transverse direction X and be constructed in a so-called shell-shaped design.

[0029] Within the housing 5, an assembly 9 is arranged, comprising a conventionally designed percussion mechanism 11 and a drive unit 13 designed as an electric motor, which is configured to drive the percussion mechanism 11. The assembly 9 is L-shaped in this case.

[0030] The machine tool 1 has a tool holder 16 in a conventionally known manner, via which a tool 17, for example a chisel or the like, can be detachably connected to the assembly 9, in particular its impact mechanism 11.

[0031] The assembly 9 enables chisel operation, whereby in chisel operation the tool 17 oscillates back and forth in the direction of a striking axis 19. In hammer drilling operation, the tool 17 additionally performs a rotating movement around the striking axis 19.

[0032] Figure 1 shows a longitudinal direction Z, a vertical direction Y, and a transverse direction X. X, Y, and Z are axes of a Cartesian coordinate system and are mutually perpendicular. Without the application of an external force, the longitudinal direction Z coincides with the impact axis 19, which is defined by a central axis of the tool 17 held in the tool holder 16 or of the tool holder 16 itself. Without the application of an external force, the vertical direction Y is parallel to an output axis of the drive unit 13.

[0033] The assembly 9 can have a separate inner housing 21, in particular made of plastic, which in particular encloses the percussion device 11 and the drive device 13 or within which the percussion device 11 and the drive device 13 are in particular arranged almost completely or completely.

[0034] The machine tool also has a side handle 27, which forms a front gripping area. The side handle 27 is connected to the housing 5 in a side handle mounting area 67 located near the tool holder 16. For the purpose of connecting it to the housing 5, the side handle 27 has a clamping band 28, which wraps around the housing 5 in the side handle mounting area 67. The clamping band 28 surrounds the impact axis 19, meaning that the impact axis 19 passes through the clamping band 28 and through the side handle mounting area 67.

[0035] A stiffening sleeve 66, made of a metal material, preferably steel, is arranged on the housing 5, which consists essentially of plastic. This stiffening sleeve stiffens the housing 5 in the side handle mounting area 67. In the present embodiment, the stiffening sleeve 66 is arranged inside the housing 5. However, it can also be embedded in the housing 5 or arranged on the outside of the housing 5. The stiffening sleeve 66 and the tension band 28 overlap in the longitudinal direction Z, and the tension band 28 wraps around the stiffening sleeve 66.

[0036] In Figure 1, the side handle 27 extends essentially in the transverse direction X, and in Figures 2 and 5, it extends essentially in the vertical direction Y. The side handle can be arranged on the housing 5 in a way that is continuously adjustable in the circumferential direction relative to the longitudinal direction Z.

[0037] The assembly 9 is movably mounted in the housing, particularly at least in the longitudinal direction Z. The assembly 9 is shown in the figures in one of its rest positions, in which the machine tool 1 is not in operation, or in which the assembly 9 is arranged in a forward end position relative to the housing in the longitudinal direction Z. During operation of the machine tool, vibrations arise from the interaction between the workpiece and the tool 17, which act primarily in the direction of the impact axis 19, i.e., in the longitudinal direction Z. These vibrations can be transmitted to the housing 5 via a rear decoupling device 35. The purpose of the rear decoupling device 35 is to reduce or dampen as much as possible the vibrations and accelerations generated in the area of ​​the assembly 9 during operation of the machine tool 1.

[0038] The rear decoupling device 35 exhibits spring and / or damping properties at least in the longitudinal direction Z (it can also act in the X and Y directions) and is designed here as a spring device with an axis of action essentially in the longitudinal direction Z. The decoupling device 35, implemented here with two cylindrical coil springs, presses the assembly 9 into the front end position relative to the housing 5. Additional decoupling devices may also be provided.

[0039] The machine tool 1 has a bearing by means of which the assembly 9, in particular its inner housing 21, is mounted on the housing 5 in a way that allows movement in the longitudinal direction Z.

[0040] The bearing in question has a rocker arm 50 made of a plastic material, wherein the rocker arm 50 is pivotally connected to the assembly 9 at a first pivot joint about the transverse direction X, specifically to the inner housing 21 of the assembly, namely in the area of ​​the impact mechanism 11. Furthermore, the rocker arm 50 is pivotally connected to the housing 5 at a second pivot joint (which is opposed by the first pivot joint) about the transverse direction X.

[0041] The swingarm 50 is fork-shaped with a neck 58 from which a first fork arm 51 and a second fork arm 52 project. The first pivot joint, at which the swingarm 50 is connected to the assembly 9, is formed at the fork arms 51 and 52. In particular, a first bearing pin 53 is arranged on the first fork arm 51, projecting into the inner housing 21 of the assembly 9, and a second bearing pin 54 is arranged on the second fork arm 52, coaxial with the first bearing pin 53, projecting into the inner housing 21 of the assembly 9. The two bearing pins 53 and 54 form part of the first pivot joint at which the swingarm 50 is directly connected to the assembly 9.

[0042] A bearing fork 80, designed as a double fork, is arranged on the housing 5. This bearing fork 80 encompasses the rocker arm 50, in particular its neck 58, and is bolted to the rocker arm 50, in particular its neck 58. This forms the second pivot joint through which the rocker arm 50 is indirectly articulated to the housing 5.

[0043] The first bearing journal 53 is surrounded by a first O-ring 61 made of an elastomeric material, which acts on one side against the first fork arm 51 and on the other side against the assembly 9 (in particular against its inner housing 21), and thus pushes the first fork arm 51 away from the assembly 9 (in the transverse direction X) towards the housing 5, so that the first fork arm 51 slides against the housing 5. Where the first fork arm 51 slides against the housing 5, a first sliding element 71 made of metal, designed as a sheet metal part, is arranged on the first fork arm 51 for sliding contact with the housing 5, and the housing 5 has first ribs 75 extending in the longitudinal direction Z.

[0044] The second bearing journal 54 is surrounded by a second O-ring 62 made of an elastomeric material, which acts on one side against the second fork arm 52 and on the other side against the assembly 9 (in particular against its inner housing 21), and thus pushes the second fork arm 52 away from the assembly 9 (in the transverse direction X) towards the housing 5, so that the second fork arm 52 slides against the housing 5. Where the second fork arm 52 slides against the housing 5, a second sliding piece 72 made of metal, designed as a sheet metal part, is arranged on the second fork arm 52 for sliding contact with the housing 5, and the housing 5 has second ribs 76 extending in the longitudinal direction Z.

[0045] Since the front mounting of the assembly 9 in the housing 5 is achieved by the rocker arm 50, the assembly 9 can, as can be seen in Figure 5, be subjected to movement by the housing 5 in and around the side handle mounting area 67. In particular, the assembly 9 can move in all three spatial directions X, Y and Z relative to the housing 5 in the side handle mounting area 67.

Claims

PATENT CLAIMS 1. Machine tool (1), in particular a rotary hammer or chisel hammer, with a housing (5) having a rear handle area (7), with an assembly (9) comprising an impact mechanism (11) and a drive mechanism (13), wherein the assembly (9) is at least partially arranged inside the housing (5) and is movably arranged relative to the housing (5), wherein the impact mechanism (11) has an impact axis (19) defining a longitudinal direction (Z), and with a bearing by means of which the assembly (9) is movably mounted on the housing (5) in the longitudinal direction (Z), characterized in that the bearing has a rocker arm (50) to which, on the one hand, the assembly (9) is pivotably connected about a transverse direction (X) extending perpendicular to the longitudinal direction (Z), and which, on the other hand, is pivotally connected about the transverse direction (X) to the housing (5).

2. Machine tool according to claim 1, characterized in that the rocker arm (50) is made of a plastic material.

3. Machine tool according to one of the preceding claims, characterized in that the rocker arm (50) is designed in a fork shape with a first fork arm (51) and a second fork arm (52), wherein the assembly (9) is pivotably mounted on both the first fork arm (51) and the second fork arm (52) about the transverse direction (X).

4. Machine tool according to claim 3, characterized in that a first bearing journal (53) is arranged on the first fork arm (51) which projects into the assembly (9), and that a second bearing journal (54) is arranged on the second fork arm (52) which projects into the assembly (9).

5. Machine tool according to one of claims 3 or 4, characterized in that the first fork arm (51) and / or the second fork arm (52) slides against the housing (5).

6. Machine tool according to one of claims 3 to 5, characterized in that a first sliding piece (71) made of metal is arranged on the first fork arm (51) for a sliding contact with the housing (5), and that a second sliding piece (72) made of metal is arranged on the second fork arm (52) for a sliding contact with the housing (5).

7. Machine tool according to claim 6, characterized in that the first sliding piece (71) is a sheet metal part, and that the second sliding piece (72) is a sheet metal part.

8. Machine tool according to claim 4, preferably in combination with one of claims 5 to 7, characterized in that the first bearing journal (53) is surrounded by a first O-ring (61) which pushes the first fork arm (51) away from the assembly (9) towards the housing (5), and that the second bearing journal (54) is surrounded by a second O-ring (62) which pushes the second fork arm (52) away from the assembly (9) towards the housing (5).

9. Machine tool according to one of the preceding claims, characterized in that a bearing fork (80) is arranged on the housing (5) to which the rocker arm (50) is pivotably attached.

10. Machine tool according to claim 9, characterized in that the bearing fork (80) surrounds the rocker arm (50).

11. Machine tool according to one of the preceding claims, characterized in that the housing (5) has a side handle mounting area (67) which can be enclosed by the tension band (28) of a side handle (27), wherein the impact axis (19) passes through the side handle mounting area (67), wherein the assembly (9) is spaced apart from the housing (5) in the side handle mounting area (67).

12. Machine tool according to claim 11, characterized in that a stiffening sleeve (66) is arranged on the housing (5) which stiffens the housing (5) in the side handle mounting area (67).

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