Patent Application
20070098512
The present invention relates to a clamping device for a tool being mounted to a machine and particularly to a clamping device, which provides a fitting ring for cushioning and assisting the tool being clamped.
Generally, the CNC (computerized numerical control) machine has been indispensable for work pieces being machined with operations such as drilling, reaming, boring and milling. Cutting tools are usually mounted to the machine with the tool handle or tool stem thereof being joined to the spindle of the machine respectively. The tool handle has a taper part at the front end thereof for being clamped by the machine and the rear end thereof is for being attached to the cutter such that the cutting tools are able to be held to the machine.
The taper part provides an advantage that precise dimension of the respective tool handle for accommodating different machines is not required and the taper part slants gradually for being inserted into the machine to form a best fit during clamping being performed. Hence, it is suitable for different machines and achieving tight fit assembly even if there is dimensional error resulting from production tool because the error is adjusted easily.
However, the preceding arrangement has a problem that the rear end is in a state of suspending without contacting with the tool handle due to only the taper part of the tool being clamped. In this way, it is very easy for the tool to occur a phenomenon of swinging and to influence precision of machining seriously.
In order to solve the preceding problem, prior art such as disclosures of U.S. Pat. Nos. 5,352,073 and 6,739,810 has proposed many ways for improvement and the most desirable way is to change clamping part of the machine tool, that is, a press part is provided at the rear end of the machine to press against the tool handle for enhancing steadiness during the tool handle being clamped. This is so-called “Dual Contact”. But, another problem is created that structure of the machine has to be changed and it is a puzzle to the manufacturers because the original machine has to be sent back to the shop for revising the structure thereof or replacing new parts. Further, in casing of the revised structure, especially the press part, being redesigned improperly, another big problem has to be faced undesirably.
An object of the present invention is to provide a clamping device for a tool, which is capable of assisting support of a clamping member and providing a function of cushion for offering much better steady machining condition and promoting machining precision.
In order to achieve the preceding object, the clamping device for a tool according to the present invention includes a clamping member and a fitting ring with the clamping member having a conical part at an end section thereof for being clamped with the machine, a holding part, which extends outward circumferentially, at a middle section thereof, and a retaining recess at another end section thereof for fixing with a tool and the fitting ring passing over the conical part and being attached to a lateral side of the holding part for the machine pressing against the fitting ring in case of the machine clamping the conical part for assisting support of the clamping member and providing a function of cushion.
The present invention can be more fully understood by reference to the following description and accompanying drawings, in which:
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It is appreciated that the fitting ring of the clamping device for a tool according to the present invention overcomes deficiency of the conventional clamping device substantially even if the fitting ring is mounted to a conventional CNC machine without changing structure of the machine.
While the invention has been described with reference to a preferred embodiment thereof, it is to be understood that modifications or variations may be easily made without departing from the spirit of this invention, which is defined by the appended claims.
