Chucks or sockets – Socket type – Self-grasping
Patent
1991-08-21
1993-02-23
Bishop, Steven C.
Chucks or sockets
Socket type
Self-grasping
279 75, 279 82, 279905, B23B 3122
Patent
active
051883783
DESCRIPTION:
BRIEF SUMMARY
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to a chuck.
Such a chuck is known from Federal Republic of Germany 29 34 428 C2, in which the window-like opening in the bushing which receives the ball debouches within the region of one of the hexagon surfaces of the cavity. The opening is developed as a slot which extends in the direction of insertion of the tool. In the region of its inner edge the inner wall is provided with support shoulders in the manner that two linearly extending support shoulders are connected together by arcuately shaped support shoulders. Since the slot is to be produced by means of an end mill, the support shoulders are of identical cross sectional shape. The slot shaped opening is provided so that the ball may carry out a movement in the insertion direction even in the event of insufficient displacement of the actuating sleeve.
The object of the present invention is to manufacture a chuck of this type, in a manner simple to manufacture, in such a way that, in addition to easy insertion and release of the tool, a large holding force acts on the inserted tool upon a pulling load acting on it in the direction of removal.
SUMMARY OF THE INVENTION
As a result of this development, the value in use of a chuck of this type is increased. Even in the case of a small size, a firm seat of the inserted tool in the cavity of the bushing is obtained. For the insertion of the tool the ball does not have to be pushed back by it. The actuating sleeve is merely displaced against spring load so that the tool can be introduced unimpeded into the cavity. When the tool is inserted, one of the corner recesses is aligned with the ball which through the released actuating sleeve comes into twopoint application against the surfaces of the corner recess on the shank end of the tool, which surfaces are in prismlike relationship to each other. In combination with the downwardly dropping clamping surface of the actuating sleeve and this two-point application, a real interlocking is obtained which is capable of taking up particularly large pulling loads. Therefore, pulling forces of 150 to 200 newtons can be exerted on the tool without it leaving the cavity.
The fact that materials of high strength are selected for the tool as well as for the ball contributes to the obtaining of this high holding force. This applies essentially also to the actuating sleeve so that the two-point application of the ball in combination with a slight entrance into the corner recess creates the firm seat. If one disregards deformation, the release of the tool must be effected intentionally, namely, by displacing the actuating sleeve against spring action, in which case the clamping surface moves away from the ball, with release thereof in radial direction. After release the tool can again be easily removed. When the actuating sleeve is not displaced in the direction of release, a force acting on the ball is not able to displace the actuating sleeve since the clamping surface has such an angle to the longitudinal axis of the chuck that a self-locking effect is thereby produced. In detail, such dimensional agreement is selected that the diameter of the ball is smaller than half the corner dimension of the shaft end and more than twice as great as the width of the corner recess in the axial direction of the shank. Therefore the above-mentioned large holding force can be produced with ball diameters of, for instance, 2 to 3 mm.
It is furthermore advantageous if the support shoulders of the cavity passing through one of the polygon edges are, as seen in circumferential direction, of different thickness. Bit-shaped tools produced with larger tolerances can also be held sufficiently firmly. This is true, in particular, of tools which are produced by cold working. If tools of large undersize are used, the ball can penetrate directly up to the support shoulders and rest there. Due to the fact that the support shoulders are of different size, there is also a different rolling behavior of the ball within the opening. S
REFERENCES:
patent: 1642490 (1927-09-01), Decker
patent: 2518134 (1950-08-01), Hallowell et al.
patent: 3251605 (1966-05-01), Ondeck
patent: 3428327 (1969-02-01), Sindelar
patent: 4209182 (1980-06-01), Sheldon
patent: 4287923 (1981-09-01), Hornung
patent: 4629073 (1987-09-01), Martindell
patent: 4629375 (1987-12-01), Lieser
patent: 4900202 (1990-02-01), Weinhold
Bishop Steven C.
Farber Martin A.
Wera Werk Hermann Werner GmbH & Co.
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