Tool driving or impacting – Impacting devices – With means for rotating tool
Patent
1994-03-25
1995-12-12
Smith, Scott A.
Tool driving or impacting
Impacting devices
With means for rotating tool
279 193, B23B 3102, B25D 1708
Patent
active
054741394
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a device on hand-held machine tools.
A tool holder which is constructed as a drill chuck and whose rotational driving elements are formed by a plurality of gripping segments lying one on top of another is known from DE-U 85 10 262. The gripping segments have an approximately trapezoidal or circular cross-sectional shape, are curved in profile, and merge with one another in curved portions. The lateral surfaces of the rotational drivers are accordingly not planar and are arranged relative to the direction of the application of force in a disadvantageous manner for the transmission of torque.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a device for power tools, which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a tool holder in a hand-held machine tool for transmitting a rotational movement and/or a percussive movement to a tool having a plurality of grooves for rotational driving which grooves are partially open toward an end of a tool shaft, which tool holder has a tool holder body with a receptacle hole provided with a plurality of inwardly projecting rotational drivers, wherein in accordance with the present invention the rotational drivers have stepped flanks and are engageable in the grooves of the tool, the rotational drivers are arranged so as to be stationary in the receptacle hole, the flanks of the rotational drivers extend approximately radially in a plane and are connected by guide portions formed by portions of a cylindrical outer surface extending in a circumferential direction around the receptacle hole.
The device in accordance with the present invention; has the advantage over the prior art that the rotational drivers are aligned in an optimal manner with respect to the requirements for an effective transmission of torque and also offer the best possible guidance and centering of the drilling tool. The device has the additional advantage that the weakening of the tool shaft caused by the rotational drivers is kept at a minimum in spite of the possibility of clamping tool shafts of various diameters. In a particularly advantageous manner, the rotational drivers have guide portions located at a distance of 4 mm, 5 mm or approximately 6 mm from the center axis of the receptacle hole. Accordingly, tools with shafts of 8 mm, 10 mm or 12 mm can be optimally guided, which ensures excellent true running. The arrangement of locking members in the region of the rotational drivers is also particularly advantageous. This also serves to keep the weakening of the tool shaft within narrow limits. Resiliently supported locking members automatically recede or yield when a tool is inserted and engage in its wake in axial locking grooves of the tool. This adds to the convenience of operation. As the axial locking members engage in the receptacle hole to various depths depending on the shaft diameter of the inserted tool, this may be used advantageously for sensing the diameter of the drilling tool and adjusting the speed accordingly. It is particularly advantageous that this sensing is effected in a purely mechanical manner and the information obtained thereby is also mechanically transmitted via a sleeve so that the sensing device is impervious to soiling and also remains functional under the harsh operating conditions of the construction site.
The present invention also deals with a tool for a drill chuck or a tool holder of a hand-held drill or hammer device, having a shaft with an insertion and provided with a plurality of grooves which are open toward the insertion end and arranged at angular intervals at a circumference of the shaft, wherein in accordance with the present invention the grooves have planar lateral walls which are arranged approximately radially to a tool axis and connected by radial portions in the shape of a cylindrical outer surfa
REFERENCES:
patent: 5076371 (1991-12-01), Obermeier et al.
patent: 5324145 (1994-06-01), Kleine
patent: 5346340 (1994-09-01), Runge
Odendahl Alfred
Wanner Karl
Robert & Bosch GmbH
Smith Scott A.
Striker Michael J.
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