Motor driven drilling hammer

a motor-driven, drilling technology, applied in the direction of percussive tools, percussive tools, bulkheads/piles, etc., can solve the problems of strong vibration transfer from the percussion mechanism to the housing and handle components, and achieve the effect of reducing vibration

Inactive Publication Date: 2007-05-17
METABOWERKE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0005] This object is achieved with a drilling hammer of the above-mentioned type in that the drill sleeve is connected on its outer periphery to a spring means of an elastomeric material which has a wall thickness of 1 to 10 mm, wherein the spring means has a damping mass which can be displaced in the peripheral and longitudinal directions of the drill sleeve relative thereto due to the elasticity of the spring means, thereby effecting damping to reduce vibrations.
[0006] In the inventive drilling hammer, the damping mass may oscillate in a translatory and also rotary direction. The spring / mass system is thereby designed, such that oscillation of the damping mass in the translatory and rotary directions is, in each case, counter-phased to the oscillations of the drill sleeve, such that these oscillating frequencies are cancelled or effectively damped. This reduces the overall oscillation excitation of the drilling hammer by these two main components. In accordance with the invention, it has turned out that, especially for small and medium-sized drilling hammers, the vibrations at the handle are primarily generated by the percussion and rotary forces acting on the tool. Since the percussion and rotational speed of drilling hammers remain largely constant during operation, the oscillations can advantageously be damped to reduce vibrations. The inventive design reduces vibrations in a highly effective fashion, since translatory and also rotary oscillations can be damped.
[0008] With particular advantage, the elastomeric material may continuously surround the drill sleeve in the peripheral direction, and be substantially cylindrical. This produces a very load-resistant connection between the damping mass and the drill sleeve, which is also largely insensitive to shearing loads. In certain cases, it may also be advantageous to segment the elastomeric material, i.e. to provide several bordering or spaced-apart segments of elastomeric material on the outer periphery of the drill sleeve or to provide the elastomeric material with perforations, recesses or openings in a radial, tangential or axial direction.
[0009] For the use of small and medium-sized drilling hammers, a wall thickness of the elastomeric material of 4 to 8 mm has proven to be advantageous. In one further preferred embodiment, the elastomeric material has an axial extension in the longitudinal direction of the drill sleeve of 5 to 20 mm.

Problems solved by technology

One problem of drilling hammers is that the percussion drive causes strong vibrations transferred from the percussion mechanism to the housing and handle components.

Method used

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Embodiment Construction

[0015] The figures show a region 2 comprising the drive components of an inventive drilling hammer. A region comprising the electromotor and a handle region of the drilling hammer are not shown. A main drive shaft extends through the indicated rotary duct 4 into the region 2 and drives a shaft 6 (in a manner not shown). The shaft 6 has a wobble plate arrangement 8 (best shown in FIG. 2) which drives a percussion mechanism 10 of the drilling hammer, and a toothed wheel 12 (only shown in FIG. 2) which rotates a drill sleeve 14.

[0016] The percussion mechanism 10 has a sleeve 18, which defines a cylindrical chamber 16 and can be moved, i.e. axially reciprocated, by the wobble plate arrangement 8 in the longitudinal direction 20 of the drill sleeve 14. The sleeve 18 is disposed inside the drill sleeve 14, concentrically thereto, and can be axially moved relative thereto. A free flight body is provided as beater 22 within the cylindrical chamber 16, which forms a pneumatic spring 24 toge...

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Abstract

The invention concerns a motor-driven drilling hammer with percussion and rotary drive, and a drill sleeve (14) which is disposed in a housing and is drivingly connected to a tool or a chuck for receiving the tool. In order to improve vibration damping, the drilling hammer is designed such that the drill sleeve (14) is connected on its outer periphery (30) to a spring means (32) of an elastomeric material (34) which has a wall thickness of 1 to 10 mm, and wherein the spring means (32) holds a damping mass (36) which can be deflected relative to the drill sleeve (14) in the peripheral direction and in the longitudinal direction (20) of the drill sleeve (14) due to the elasticity of the spring means (32), thereby effecting damping and reduction of vibration.

Description

[0001] This application claims Paris Convention priority of EP 05 024 979.6 filed Nov. 16, 2005 the complete disclosure of which is hereby incorporated by reference. BACKGROUND OF THE INVENTION [0002] The invention concerns a motor-driven drilling hammer with a percussion and rotary drive, and a drill sleeve which is disposed in a housing. [0003] One problem of drilling hammers is that the percussion drive causes strong vibrations transferred from the percussion mechanism to the housing and handle components. It has been proposed to provide a demolition hammer with a spring / mass system, wherein the oscillations caused by the axially operating percussion drive are damped by a mass which is pretensioned on both sides by springs. [0004] It is the underlying purpose of the present invention to effectively reduce vibrations in drilling hammers. SUMMARY OF THE INVENTION [0005] This object is achieved with a drilling hammer of the above-mentioned type in that the drill sleeve is connected ...

Claims

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Application Information

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IPC IPC(8): E02D7/02
CPCB25D17/24B25D2217/0092B25D2222/57
InventorKELLER, MICHAEL
OwnerMETABOWERKE