DE3241590A1 - CLAMPING DEVICE FOR A LATHE - Google Patents

Description

■. '■ [. ■■;. ;; 32415S0

10.117 Description

Clamping device for a lathe 5

The present invention relates to a clamping device for a lathe, particularly for a numerically controlled lathe.
10

In conventional machine tools, a "spiral" designated spiral toothing in the jaw feed mechanism of the jigs used. Problems arise here with regard to the service life of the arrangement and the clamping force. Therefore, such jigs not found widespread. This is due to the fact that the known device insofar there is a disadvantage as the pitch angle of the spiral. with changing diameter changes, and the pitch angle does not match the pitch angle of the one engaged with the spiral Drive arrangement can be adapted, with the result that there is no surface contact between the two parts, but line contact comes into being. For this reason, the service life of the arrangement is reduced noticeable, and if a large clamping force is required, it may even seize, which affects the economy the machine deteriorates.

The invention is based on the object of eliminating the problems outlined above, a clamping device to create for large clamping forces by the line contact encountered in known arrangements through

BATH ORIGINAL

Replaces surface contact and thereby the service life of the Jig is raised. The invention is also intended to make it possible to carry out workflows without the need for personnel by the Position of the clamping jaws is automatically adapted to the respective workpiece diameter. In addition, the Invention to increase the economy of clamping devices by clamping devices with different '0 capacity to be replaced from time to time.

This object is achieved according to the invention by the in the characterizing Part of claim 1 specified features solved.

'5 Advantageous developments of the invention are in the Subclaims indicated.

In the following, exemplary embodiments of the invention are explained in more detail with reference to the drawing. Show it: 20th

Figure 1

a partially sectioned side view of a jig and a cylinder device mounted on the spindle of a lathe,

Figure 2

a longitudinal sectional view of the clamping device,

Figure 3

a perspective partial view of a drive pawl and of a management member /

Figure 4

a longitudinal sectional view of the cylinder device, 35

Figure 5

a longitudinal sectional view of a further embodiment of the Jig, ■

Figure 6 '";

a longitudinal sectional view of a further embodiment of the clamping device.

Figure 1

shows a preferred application of a clamping device (2) and a cylinder device 3 mounted on the spindle 1 of a lathe. The spindle 1, the jig 2 and a rotary valve 4 are rotated by a motor not shown. A sleeve body 5 of the cylinder device 3 and a holder of the drive motor 6 of a drive shaft to be described later are firmly mounted on the lathe. A clamping jaw 8 holds a soft jaw 7. The soft jaw and the clamping jaws clamp or loosen a workpiece with the reciprocating motions and the rotary motions a drive shaft 9, and the working position of the clamping jaw is changed accordingly. This is supposed to are explained in detail below with reference to FIG. 2 and the remaining figures.

Figure 2

shows a longitudinal sectional view of a preferred embodiment of a clamping device according to the invention.

Figure 3

shows a partial perspective view of a drive pawl lind a guide member that is in the jig come into use. In the end face of a clamping body 20 there are several (in this embodiment three).

Grooves provided. The clamping jaw 8 on which the soft jaw 7 is attached by means of threaded pins 10 is

4/5 ■ _ ■■.

inserted into a corresponding groove so that it can be slid in the radial direction. The back of the Clamping jaw 8 is designed as a toothed rack 11 which is connected to one on the outer circumference of a drive wheel 22 trained worm gear is in engagement. The drive wheel 22 is centric and rotatable on the in the Drive pawl 21 mounted in the groove. The rack arrangement is designed so that it is considerable large back and forth movements of the soft jaws in the radial direction of the clamping body 20 when the drive wheel 22 rotates.

The rotation of the gear 22 is carried out by a ring gear 23, which with it in the manner of a straight tooth face wheel is engaged. The ring gear is rotated by the torque of a to be described Drive device driven drive shaft

9 is transmitted to the ring gear via a center gear 24 and an intermediate gear 25.

When the drive shaft 9 rotates clockwise, the clamping jaw 8 moves in the radial direction opening outwards (this is indicated by the arrow "x"). When the drive shaft turns counterclockwise rotates, the clamping jaw moves 8. closing in the radial direction inwards (this is through the arrow "y" indicated). Since these outward and inward movements of the clamping jaws 8 the must take into account changing diameter of the workpieces, the range of motion is considerably large, for example 50 mm to 100 mm.

Although such a large range of motion is required, the jig according to the invention can be more satisfactory Work wisely and quickly press the soft jaws or clamp workpieces. Once the one

clamping diameter of the workpieces is determined short stroke of movement of, for example, about 5 mm to the repeated clamping or releasing of workpieces.

The following description relates to the mode of operation the clamping jaw 8 when workpieces are clamped within a very small stroke range. The clamping body has a through opening 12 which extends in the axial direction and in which a guide member 26 is arranged is, which is guided by the wall surface "a" of the through hole 12 in the axial direction slides. The guide member 26 is arranged on an end face 13 of the drive shaft 9 and such designed that it is rotatable, on axial movements however, is prevented by an annular projection 27 and a nut 28 which is in engagement with the shoulder 13 via the intermediate gear 24. On the other hand, owns the guide member also has a convex keyway "d" with which a located at the lower end of the drive pawl 21 Protrusion "p" engages. The convex keyway "d" is shaped in such a way that it tapers in the direction of the end face "A" of the clamping body 20 and gradually approaches the axis of the drive shaft 9 at its tip (see Figure 3). If the Drive shaft 9 is operated so that it is in the Clamping body 20 is pushed in, the drive pawl moves radially outward due to the wedge effect, which occurs when the keyway "d" of the guide member 26 in contact with the projection "p" the drive pawl, 21. comes .. Along with this movement of the drive pawl 21, the clamping jaw moves 8, which is in engagement with the drive wheel 22, the axis of rotation of which is the drive pawl 21, radially

^ 5 to the outside ("x"), whereby the open state of the clamping device is brought about. On the other hand, if the

Drive shaft 9 is pulled out of the clamping body 20, the drive pawl 21 moves radially inward ("y"), whereby the clamping jaw 8 is displaced radially inward, so that the clamping device reaches its closed state. Since the drive wheel 22 is in the non-rotating stationary state during this movement process, the displacement path of the drive pawl 21 is the same as that of the clamping jaw 8.
10

Figure 4

Fig. 13 is a partial longitudinal sectional view showing the cylinder device which extends the drive shaft around a certain point fixed stroke reciprocated as described above, and the drive shaft clockwise or counterclockwise.

According to Figure 4, the sleeve body 5 is mounted on the lathe, and the rotary valve 4 is rotatably mounted, whereby it penetrates the stationary sleeve body 5. In the cylinder "S" of the rotary valve 4 is a piston

32 is provided which can slide in the rotary valve. Thus the piston moves in the direction of the arrow ("V" and "W") reciprocating due to fluid pressure from an external source (not shown). To achieve A guide pin 14 and guide openings 15a and 15b are provided for a uniform back and forth movement of the piston 32. The to-and-fro movements of the drive shaft 9 enable the clamping jaw 8 to be displaced in it radial direction due to the guide member 26. At the rear end of the drive shaft 9 is a Coupling part 36 fastened so that it protrudes from the sleeve body 5, while another coupling part 37 is rotatably mounted on an arm 16 of the lathe on the opposite side "B". Between the coupling part 36 and the coupling part

- Q -

37 there is a certain free space "h". The coupling part 37 is driven and rotated by the motor 6 attached to the lathe, and the torque /, is then transmitted to the drive shaft 9 in the manner described below.

Assume that "e" is the displacement that is necessary to actuate the guide member 26 described with reference to FIG. 2, and the displacement "f" of the Piston 32 becomes equal to "e" (i.e., "f" = "e"). ? Then it will be a workpiece is clamped or clamped during such a displacement of the clamping jaw 8 in the radial direction solved, which corresponds to the above displacement "f". Furthermore, the piston 32 is designed and arranged in such a way that that it also allows an additional displacement "g" in addition to the displacement "f" of the rotary valve. As a result of the additional displacement “g”, a tooth “t” of the coupling part 36 comes into engagement with it one. Tooth gap "j" of the coupling part 37.

That means: these components are designed so that between the Zusatzverschiebuhg "g" and the clear distance "h" between the two snap couplings 36 and 37 the relationship "h" = "g" applies.

When the motor 6 is driven while the coupling part 36 is engaged with the coupling part 37, the drive shaft 9 rotated accordingly, and the center wheel 24 is rotated in the clamping body 20, whereby the Ring gear 23 is rotated via the ■ idler gear 25. Follow the drive wheel 22 is rotated about the drive pawl 21. The rotation causes the Clamping jaw 8 in the radial direction, since the worm threads of the drive wheel 22 with the rack of the input * clamping jaw 8 are engaged. The clamping jaw 8

.35 shifts in the direction of the arrow "x" when the

'Motor 6 rotates clockwise / it shifts in the "y" direction when the motor 6 is counterclockwise rotates, whereby the position of the jaws 8 changes. Since this amount of jaw displacement is caused by the The extent to which the motor 6 is driven is determined, a position detector (pulse encoder or the like) 38. mounted, and the desired or required displacement is determined by detecting the displacement by means of the position detector

'"appropriately considered. By means of an arm .60 is a stroke detector on the coupling side of the sleeve body

39, for example a photocell, a proximity switch or the like, mounted to automatically control the displacement of the piston 32.

In order to prevent the drive shaft 9 from rotating when the clamping device and the cylinder device .3 rotates, a braking device is provided between the sleeve body 5 and the snap coupling 36.

'- ^ The braking device consists of a sliding plate 40 attached to one side of the sleeve body 5 and a tubular sleeve 43 which has a flange "s" and is equipped with a lining 42 which, by the force of a spring 41, is in contact with the normal state Slide plate 40 is brought. The tubular sleeve 43 with the flange "s" has at its tip on the inner circumference provided projections "k" which engage in keyways .44 which are milled into the drive shaft .9 over a certain length. This is a

^ "Axial shifting possible. On the end of the with the Flanged tubular sleeve 43 sits a clamping nut 45 .. In a drilled in the slide plate 40 A spring 41 is inserted into hole "v", which is in this way supported by the terminal nut 45 of a seal 46 and a ring 47

is received in the hole that they are compressed

BATH ORIGINAL

in order to achieve a braking effect in the normal state, by placing the lining 42 of the flanged tubular sleeve 43 in pressure contact with the slide plate

40 is brought.
5. ·· ""

When the drive shaft 9 rotates counterclockwise, i.e., moving backward in a direction in which the clutch parts 36 and 37 are engaged, comes on Annular stop 48 attached to the drive shaft 9 in contact with the leading edge "m" of the flange-mounted one Pipe sleeve 43, just before the coupling parts come into engagement. The ring stop 48 takes the tubular sleeve provided with the flange 43 with overcoming the force of the spring 41, whereby the Lining 42 detaches from sliding plate 40 and therefore no braking takes place.

The following describes the operation of a preferred embodiment of the invention will be described. 20th

At a work station, a robot grabs workpieces that are arranged in a pallet magazine and gives them the workpieces concerned one after the other in a chuck of a machine tool (ζ. B. a lathe), and ei " sets the previously machined workpiece, which was picked up by the clamping chuck, through a subsequent, unmachined workpiece, so that the operation of the machine is continuous. This process involves clamping an unprocessed workpiece in the clamping jaw and for releasing a previously processed workpiece from the Clamping jaw a clamping, loosening or unclamping process is necessary. In the present case, the direction of flow of the piston in the cylinder device is below Pressure supplied fluids automatically and selectively from a (not shown here) control unit on the basis of received signals that are output

when the robot grips an unprocessed workpiece or lets go of a previously processed workpiece. These Signals reach the control unit as input signals and cause the clamping jaws to be moved in di © "5 open or closed position.

In a preferred embodiment of the invention a fluid channel valve for the piston 32 in the rotary valve. 4 based on command signals presented as Input signals come from the robot, selectively switched to thereby cause the drive shaft

9 reciprocates together with the movement of the piston 32, whereby the clamping jaw 8 in the radial direction the jig goes back and forth. This enables the workpieces to be clamped in the correct sequence and be relaxed. In addition to the case described above, the command signals can be derived from the movements of the pallet magazine or from a sequence control or a program.

As shown above, the automatic actuation of the clamping jaws, controlled by a control unit with external signals, allows different workpieces of different diameters to be arranged in a pallet magazine so that they can be clamped and processed. The clamping jaws are actuated as soon as signals are received which inform the clamping device in advance about different diameters. The change or deviation of a Einspanndurchmessers when the robot grasps a work piece, or the change in shape which is transported by a pallet magazine of the workpiece is converted to command signals to start the motor. 6 The drive shaft then rotates as described above to change the clamping position of the clamping jaws so that they take into account the diameter of the workpieces

wearing.

The drive shaft 9 can take the place of the piston 32 of the rotary valve 4 according to FIG. 4 can be separated. The drive shaft 9 can by means of rings 31a and 31b with a be connected to the shaft penetrating the sleeve body, a pin 35 being provided at the relevant point is, and the shafts can be constructed as a unit * by using a terminal nut 33 at the end, see above that the jig and cylinder can be easily removed by: just the locking nut 33 is removed. This means that different clamping devices of different capacities or diameters on the same cylinder by simply exchanging the '

15. Jigs can be used. In this way the economy of the arrangement becomes very strong improved. Although the above description relates to an embodiment in which the rotation of the drive shaft 9 takes place by engaging the coupling parts 36 and 37, can instead of the case described as a snap coupling or claw clutch formed clutch a slip clutch with a friction plate or a magnetic clutch can be used. Deviating from the above transmission mechanism for the rotary movement of the drive ^ shaft, the rotary movement of the drive shaft to the and moving the clamping jaws in the radial direction are implemented by a combination of a bevel gear and a spline.

^ As can be seen from Figure 5, an L-shaped lever

50 are used to shift the clamping jaws by small distances in the radial direction of the clamping body to achieve according to the back and forth movements of the drive shaft 9. With this preferred In the embodiment, the L-shaped lever 50 is mounted pivotably about a pin 51 in the clamping body 20.

Halfway up the drive wheel 22 is in this one

concave or notched portion "Q" is formed. The L-shaped lever 50 is designed and arranged in such a way that that it engages with one end in the concave or notched portion "Q", while its other end with a projection "R" of the nut 28 is engaged. In this embodiment that is shown in FIG Intermediate wheel 35, which was used to rotate the drive wheel 22, is omitted. The rotation of the drive wheel 22 takes place through the center wheel 24 and the ring gear. On the toothed surface of the drive wheel 22 is both in this exemplary embodiment as well as in the exemplary embodiment according to FIG. 2, a tooth section "U" is provided, so that it can mesh with the teeth of the ring gear in the axial direction, ie perpendicular to the extension the toothed surface of the drive wheel 22.

Although the previous embodiment is a considerable one Stroke of the reciprocating movement in the radial direction of the clamping jaws in accordance with the rotation of the Drive shaft 9 was provided, FIG. 6 shows a further embodiment in which the ring gear shown in FIG 23. L-shaped, so that it protrudes with respect to the clamping body 20 to the outside and his teeth "i" can mesh with a gear 54 if this protrudes from the spindle head from time to time. The longitudinal movement (Reciprocation) of the gear 54 is performed by reciprocating fluid cylinders 55a and 55a 55b while the gear 54 is rotated by a small motor through a spline shaft 57. The arrangement of the Control unit for automatic execution of these movements if input signals are received from outside, corresponds to the exemplary embodiment according to FIG. 1.

Blank page

Claims (6)

BLUMBACH · V ¥ E? SER ^: -BHRBEN · KRAMER ZWIRNER HOFFMANN PATENT LAWYERS IN MUNICH AND WIESBADEN Patentconsult Badeckestraße 43 8000 Munich 60 Telephone (089) 883603/883604 Telex 05-212313 Telegram'Patentconsult Palentconsult Sonnenberger Straße 43 6200 Wiesbaden Telephone (06121) 562943/561998 Telex 04-186237 Telegrams Paienlconsult KITAGAWAIRONWORKSCO., LTD. 10.117 Fuchu-shi, Horishima-ken / Japan Dr / sc / Kr / sa Clamping device for a lathe Claims 1 . ) Clamping device for a lathe, characterized in that a plurality of grooves extending in the radial direction are provided on the end face (A) of a clamping body (2), that in each of the grooves on a pivot pin (21) a drive wheel (22) designed as a worm is rotatable is mounted, the threads of which on the front side of the drive wheel (22) with a longitudinally extending rack (11) of a clamping jaw (8) are in engagement that with the back of the drive wheel (22) a ring gear (23) meshes with the a centrally mounted in the clamping body drive shaft (9) or by another drive device (54) is rotated so that the drive wheel (22) rotates, whereby the clamping jaw (8) is strongly reciprocated in the radial direction The drive shaft (9) can be moved back and forth in the axial direction, and that the bearing of the drive wheel (22) is designed in such a way that it is within the b efind- * borrowed grooves, as a result of the back and forth movement of the drive shaft (9), can be pushed back and forth radially by small distances. Munich: R. Kramer Dipl.-Ing. ■ W. Weser Dipl.-Phys. Dr. rer. nat. · E. Hoffmann Dipl.-Ing. Wiesbaden: PG Blumbach Dipl.-Ing. · P. Bergen Prof. Dr. jur. Dipl.-Ing ,, Pat.-Ass., Pat.-Anw. until 1979. G. Zwirner Dipl.-Ing. Dipl.-W.-Ing. 2. Clamping device according to claim 1, characterized characterized in that the drive shaft (9) with an axial reciprocating movement allowing Cylinder arrangement (4, 32) is equipped. "■ - ■ 3. Clamping device according to claim 1 or 2, characterized characterized in that the drive shaft (9) is equipped with a clutch arrangement (36/37). 4. Clamping device according to one of claims 1 to 3, characterized in that the drive shaft (9) is equipped with a stroke detector (39) which detects the amount of drive shaft displacement in the axial direction. 5. Clamping device according to one of claims 1 to 4, characterized by a position detector (38) for the drive shaft (9) to measure the angle of rotation of the drive shaft. 6. Clamping device according to one of claims 1 to 5, characterized / that the drive shaft (9) is equipped with a connection (40 to 46) which can be separated in the longitudinal direction of the shaft. BATH ORIGINAL