Cutting by use of rotating axially moving tool – Tool or tool with support – Including detailed shank
Patent
1993-04-07
1994-08-23
Bishop, Steven C.
Cutting by use of rotating axially moving tool
Tool or tool with support
Including detailed shank
2791193, B23B 4516, B23B 5102
Patent
active
053402456
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a device on portable machine tools.
More particularly, it relates to a device on portable machine tools, in particular portable drilling or percussive appliances, which is suitable for transmitting a rotary and/or a percussive movement to a tool having rotary driving grooves open toward an end of the shank and a location hole with inwardly projecting rotary driving elements engaging in the grooves of the tools.
Devices of the above-mentioned general type are known in the art. One such device is that disclosed for example in WO DE88/00260. However, it is only possible to insert into these tools with open grooves distributed non-uniformly over the circumference. The rotary driving elements of the known device are arranged asymmetrically and thus prevent universal use. In particular, the tools suitable for this device are not compatible with other tool holders such as drill chucks. On the one hand, there is the risk that some of the chuck jaws will engage in the existing grooves, leading to eccentric gripping, and, on the other hand, there is no axial mobility of the tool in drill chucks. However, a limited axial mobility is very advantageous in the case of impact drilling tools since then, when striking, only the tool itself and not, in addition, parts of the chuck have to be moved.
Tools are inserted into the device. Another tool is known from DE-A-34 29 419. This tool can be gripped in drill chucks with three jaws and inserted into tool holders of certain hammer drills. The tools have a closed groove for locking in the hammer drills. In percussive operation, this groove for the rotary driving and locking elements is subjected to severe loading. Since it is only partially closed, there is the risk, in the case of worn-out shanks, that the tool will be released unintentionally. Furthermore, the known tools are not suitable for hammer drills with tool holders which have inwardly facing rotary driving strips.
It is disadvantageous for use in machines with drill chucks that the design of the grooves in the shank PG,3 of these tools permits only fixed gripping without axial mobility of the tool. However, a limited axial mobility is very advantageous in the case of impact drilling tools since then, when striking, only the tool itself and not, in addition, parts of the chuck have to be moved. There is thus no axial securing of the tool when it is used in drill chucks. The known shank design is thus not suitable for universal application and as a standard shank shape for various types of portable drilling or percussive appliances and all applications.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a device for portable machine 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 device of portable machine tools, in particular portable drilling or percussive appliances, suitable for transmitting a rotary and/or a percussive movement to a tool having three rotary driving grooves open toward the end of the shank and a location hole with inwardly projecting rotary driving elements with essentially flat flanks, which rotary driving elements engage in the open grooves of the tool, wherein in accordance with the present invention, the rotary driving elements are arranged in a rotationally symmetrical fashion, are of equal width and have flanks which extend approximately parallel to one another.
When the device is designed in accordance with these features, it has the advantage that it can be used to transmit high torques to specially designed tools with three open grooves distributed uniformly over the circumference in a manner which reduces stress on the shank. At the same time, there is a limited axial mobility of the tool for impact drilling or chiselling. The device according to the invention is thus suitable for optional use of tools suitable for drill chuck
REFERENCES:
patent: 4106573 (1978-08-01), Bailey
Bloechle Hans
Wanner Karl
Bishop Steven C.
Robert & Bosch GmbH
Striker Michael J.
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