Chucks or sockets – Radially reciprocating jaws – Jaws
Reexamination Certificate
1999-10-20
2001-06-05
Bishop, Steven C. (Department: 3722)
Chucks or sockets
Radially reciprocating jaws
Jaws
C279S153000, C269S284000
Reexamination Certificate
active
06241261
ABSTRACT:
The present invention concerns a chuck with driveable base jaws movably inserted in radially aligned grooves in a chuck body, with a releasable top jaw positioned on each base jaw in order to hold a workpiece.
The top jaws of a chuck are often configured for various working processes and adapted to the diameter of a tool section which is to be clamped in them, and are in many cases supported against the base jaws in the direction of rotation and in the radial direction by means of intersecting guide gibs and grooves arranged on the top jaws and the base jaws, onto which they are fixed by screws. Although this type of connection has proved itself in practice, machining the components on the base and top jaws which form the groove/spring connection takes a great deal of time and is therefore expensive, since it is essential to maintain precision in the production dimensions. A further disadvantage lies in the considerable length of time required to change the top jaws, because as a rule the fixing screws have to be unfastened individually if the tool is aligned horizontally and then retightened again after the replacement, whilst in addition the chucking surfaces and/or the contact surfaces of the top jaws are impaired by the chucking screws and the holes which accommodate them.
The task of the present invention is therefore to configure the base and top jaws of a chuck of the aforementioned type in such a way that not only can the interacting components of the base and support jaws be manufactured and machined in an economical fashion, but also the chucking jaws of a chuck can be replaced in a very short time. The amount of work required in order to achieve this is to be kept low whilst nevertheless a secure attachment of the top jaws onto the base jaws is to be guaranteed at all times in conjunction with straightforward handling.
In accordance with the present invention, this is achieved in a chuck of the type mentioned initially in that a joining piece is formed onto each base jaw protruding in the direction of the top jaw, with this joining piece engaging in an accommodation opening worked into the top jaw, and in that the top jaws can be clamped onto the base jaws or the joining pieces by quick clamping devices arranged in the top jaws and on the joining pieces which act in the axial direction of the top jaws and the joining pieces.
It is advantageous for each of the top jaws to be provided with an accommodation groove for the base jaws which is, in a preferred embodiment, formed by guide gibs arranged laterally in the external edge zones of the top jaws, and for the joining pieces of the base jaws to be formed as cylindrical pins and the accommodation openings of the top jaws to be formed as blind holes.
Each of the quick clamping devices can beneficially be made from a self-aligning pin which is held in radially aligned holes in the joining pieces in such a way as to permit limited sliding movements, with the ends of the pins having a recessed or a projecting cone, and from two holding screws guided in diametrically opposed threaded holes in the top jaws, with these screws possessing a projecting cone or a recessed cone corresponding to the recessed cone or projecting cone of the self-aligning pin, and located with an axial offset in relation to the self-aligning pin by means of which the top jaws are pressed on.
A further feature, which is for example advantageous during overhead working, ensures that the top jaws remain held in position on the joining pieces after the quick clamping devices have been released and is effected in that each of the top jaws are provided with a spring detent which engages in a circumferential groove worked into the joining pieces.
If the base jaws and the top jaws of a chuck are configured in accordance with the present invention, then a reliable and high-strength connection is provided between the two, which is economical to produce and, above all, can be connected and released easily and within a short time. This is because the joining pieces of the base jaws and the accommodation openings of the top jaws can be machined to precise dimensions without difficulty, whilst most of the quick clamping devices are easily accessible from above. Consequently, the top jaws can be changed without difficulties.
This is because during a jaw change, it is only necessary to release the quick clamping devices, e.g. using an Allen key which can be inserted radially from the outside into the chuck body, whilst moving the chuck body in the axial direction allows the top jaws to be pulled off the joining pieces. Differently configured top jaws can be inserted onto the joining pieces and the quick clamping devices can be reactivated, e.g. by a rotational movement, in order to complete the jaw change.
The specially configured quick clamping devices mean that each of the base jaws and top jaws form a unit which is chucked in itself, which means that a high degree of rigidity is assured between these components and no impurities can achieve ingress between them.
Furthermore, it is advantageous that the joining pieces of the base jaws which are configured as cylindrical pins and the corresponding holes worked into the top jaws can be manufactured to precise dimensions without difficulty and in an economical fashion, and that the quick clamping devices are made up of tried-and-tested components. As a result, inexpensive production is assured, whilst as a particular advantage, these components can be held in stock as prefabricated parts and it is only necessary to adapt the top jaws to the individual workpiece which is to be clamped in them. As a result, the ability to make deliveries at short notice is always guaranteed. With a simple design and configuration, the chuck configured in accordance with this proposal not only permits reproducible and precise chucking of a workpiece, but also makes it easily possible to adapt the chuck to differently shaped workpieces by means of changing the top jaws in an unproblematical procedure.
REFERENCES:
patent: 4029325 (1977-06-01), Rohm
patent: 4159161 (1979-06-01), Timmer
patent: 4200300 (1980-04-01), Rohm
patent: 4667971 (1987-05-01), Norton et al.
patent: 4667972 (1987-05-01), Hiestand
patent: 5174589 (1992-12-01), Gulde
patent: 5330205 (1994-07-01), Norton
Bishop Steven C.
Pandiscio & Pandiscio
SMW Autoblok Spannsysteme GmbH
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