DE1239169B - Chuck for centric, deformation-free and automatic clamping of thin-walled workpieces - Google Patents

Description

GERMAN PATENT OFFICE

EDITORIAL

German class: 49 a -29/01

Number: 1239 169

File number: V17668 I b / 49 a

1239 169 Filing date: December 2 , 1959

Open date: April 20 , 1967

The invention relates to a chuck for centric, deformation-free and automatic Clamping thin-walled workpieces, especially when grinding roller bearing rings with high precision, whereby the workpiece is centered in the bore and clamped by means acting on the face.

Chuck, in which the workpiece by means of coupled radial and axial movements of the centering and clamping elements is included are known.

Thus, the time carried out prior to the end-side clamping centering is achieved in the bore surface in that under spring pressure balls are axially and radially movable on a fixed cone, with the guidance of the balls takes place in an elongated foraminous cage.

Chuck of this type have the disadvantage that the centering-determining surfaces of a strong Subject to contamination and that after the assembly of the chuck on the machine tool there is no possibility of the blow resulting from various causes Eliminate blurring. This blow can be caused once by the fact that the feed cannot be put back in the same, once adjusted position after the conversion has taken place can. On the other hand, it can be caused by the fact that balls with differing Dimensions are used, whereby even the smallest diameter deviations lead to impermissible deformation of the thin-walled workpiece. The main cause of impermissible deformation of the workpiece and thus the blow consists in the relatively rapid wear of the Balls and / or the surfaces that determine the position of the balls.

Another disadvantage is that the known chuck does not cooperate with automatic loading devices can be used.

According to the invention, the disadvantages of the known chucks shown are avoided by that the centering elements are formed by centering pins which are non-rotatably mounted in the chuck body Displacement in the centering position through the wedge surface of a spring under pressure, takes place in the chuck body axially displaceable bush. To eliminate the impact by grinding are the centering pins by means of pressure pieces and clamping screws arranged coaxially in the chuck body radially lockable.

The solution according to the invention has, compared to the chuck, a centric, deformation-free
and automatic clamping of thinner walls
Work pieces

Applicant:

VEB Berlin machine tool factory,
Berlin, Berliner Chaussee 12

Named as inventor:

Georg Köster, Wildau (Kr.Königswusterhausen)

known chucks of the type described have the advantage that contamination of the surfaces determining the centering and thus increased wear is avoided and that the blow caused by the various causes ver can be eliminated by repeatable grinding in the clamping position.

Furthermore, it is advantageously noticeable that, due to the upstream of the tapered bushing,

As the spring limiting the centering pressure in connection with the ground centering pins, an elastic and deformation-free centering as well as automatic tensioning is achieved in connection with automatically acting front tensioning devices.

In the drawing, an embodiment of the subject matter of the invention is shown. It shows
F i g. 1 shows a longitudinal section through the chuck, FIG. 2 the section AB according to FIG. 1.
The chuck consists of a chuck body 1 in which a tie rod 3 secured against rotation by a pin 2 and a bushing 4 as well as two or three slides 5 are guided. Between the head 22 of the tie rod 3 and the socket 4, a weak, coordinated helical spring 6 limiting the centering pressure is attached. In the front part of the chuck body 1, six radially arranged centering pins 7 are guided in corresponding bores, which are secured against rotation by means of a pressure piece 8 and a threaded pin 9 and clamped in the centering position for the purpose of smoothing round. In the head 22 of the tie rod 3, two or three clamping claws 10 are attached, which are brought into the clamping position by the slide 5 and clamp the workpiece 23 against a fixed stop ring 11. Two or three leaf springs 12 are attached to the head 22 by means of washers and nuts 13, which hold the clamping claws 10 in their bearings

709 550/96

Claims (2)

to back up. A helical spring 15 and a shoulder on the tie rod 3 are used via an intermediate bushing 21 to return the centering and tensioning elements to their initial position. The socket 4 and the centering pins 7 are protected against contamination by rubber seals 16 and 17. The mode of operation of the chuck is as follows: the workpiece 23 is pushed onto the mounting pin of the chuck via the clamping claws 10 held in the starting position by the leaf springs 12 and pushed against the stop ring 11. By actuating the pull rod 3, the centering and clamping process is initiated, and the clamping claws 10 mounted in their head 22 slide with their machined surfaces onto the lugs of the slide S and are spread outwards. At the same time, the bush 4 is pushed back by the head 22 of the tie rod via the helical spring 6 and the centering pins 7 are guided against the workpiece 23 by means of the conical sliding surface. During this process, the clamping claws 10 come to rest with their clamping lugs on the end face of the workpiece 23. In the course of the centering and clamping process, the coil spring 6 is now compressed by further actuation of the pull rod 3 and thus the previously adjusted centering pressure is transmitted to the centering pins 7 by moving the bushing 4 and the workpiece 23 is centered as well as those detected by the head 22 and guided in the chuck body 1 Slide 5 pushed back, the clamping claws 10 spread further by sliding on the end face of the workpiece 23 until they rest with their back surfaces on the opposing surfaces of the recesses in the head 22 and clamp the workpiece 23 against the stop via the pressure points 18, 19, 20. After the end of the work process, when the workpiece 23 is unclamped, the function proceeds in reverse order, the clamping claws 10 are folded up by the leaf springs 12 after being released from the workpiece 23, the bushing 4 is advanced through the attachment on the tie rod 3 and the centering pins 7 are lifted, so that the workpiece 23 can be easily removed from the chuck. At the same time, the slide 5 guided in the chuck body 1 is pushed forward by the helical spring IS via an intermediate piece 21 and the chuck is ready for a new loading. Patent claims: 1. Chuck for central, deformation-free and automatic clamping of thin-walled workpieces, in which the workpiece is centered in the bore surface by radially displaceable elements and can be pressed against the counter-stop surface by clamping means acting on the face side, characterized in that the centering elements of the chuck body (1) non-rotatably mounted Centering pins (7) are formed, the displacement of which takes place in the centering position through the wedge surface of a bushing (4) which is under the pressure of a spring (6) and can be axially displaced in the chuck body (1). 2. Chuck according to claim 1, characterized in that the centering pins (7) are radially lockable by pressure pieces (8) and clamping screws (9) arranged coaxially in the chuck body. Considered publications:
U.S. Patent Nos. 1235,957, 2,559,942. 1 sheet of drawings 709 550/96 4.67 © Bundesdruckerei Berlin