JPH0419028A - Rotary pneumatic and hydraulic clamp device for workpiece use - Google Patents

Abstract

PURPOSE: To ensure an accurate operation of a chuck with a small capacity by making the chuck perform a clamping action through driving in a boost manner a secondary piston by the use of a primary piston pneumatically driven. CONSTITUTION: This device comprises a primary piston 4 and a secondary piston 9 constructed based on a piston sectional area ratio to bild up a boosting force in a cylindrical frame 1. The device also comprises a primary air chamber 33 at a rear part of the primary piston 4 and two secondary air chambers 34, 35 disposed at a foward part of the primary piston 4 and a foward part of the secondary piston 9, respectively. The primary piston 4 is pushed upward through compression air led into the primary chamber 33, to thereby generate pressure in oil chambers 31, 32, and the pressure is applied to the piston 9 to act a conical portion 9a on a jaw of a chuck 3. Compression air is fed into the secondary chambers 34, 35 in order to unclamp the chack 3, and then the primary and secondary pistons 4, 9 are returned to release the chuck 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The subject of the invention is a rotary pneumatic-hydraulic clamping device for a workpiece in a machine tool, in particular a bidirectionally pneumatically driven clamping device and a hydraulic clamping device on a second piston driving a chuck. The indexing table is intended to be composed of primary pistons that act as a force and have a piston cross-section ratio such that these pistons constitute a booster.

A device of this type is described in the German patent application published under number 1.477.232. In this configuration, the second piston drives the chuck and consists of a hollow cylindrical cavity consisting entirely of a long tube that is displaced by the reaction force. This arrangement is of considerable size, making it completely impossible to mount the device on the machine tool workpiece. Furthermore, the pneumatic pressure that ensures the release of the chuck acts exclusively on the primary piston and only on a small part thereof, so there is a risk that the secondary piston will become locked, making the chuck opening unreliable.

French patent number 2.186.862 (LEJEUNE
) describes a hydropneumatic clamping device of the above type in which clamping and unclamping is ensured in all situations by the action of two air chambers, a primary air chamber and its inlet connected by a quick coupling to an air supply source. has been done. The frame of this device is provided with a dovetail groove that can be fixed to a machine working table by means of a self-locking clamp.

However, this device is not suitable for use with numerically controlled indexing tables, circular work tables, or for performing indexing.

The aim of the invention is to eliminate these drawbacks.

SUMMARY OF THE INVENTION A pneumatic-hydraulic clamping device according to the invention comprises an annular chamber surrounding a chuck and divided by an intermediate fixing part into two cylinders of different cross-sectional area in which a primary piston and a secondary piston are housed, respectively. , consisting of a primary air chamber at the rear of the primary piston, and two secondary air chambers, one at the front of the primary piston and the other at the front of the secondary piston,
The frame of this device is mounted rotatably within the collar and communicates on the one hand with an air supply provided on said collar and on the other hand irrespective of the angle of rotation of the frame with respect to said chamber and its collar. It is characterized by comprising pneumatic communication means.

In a preferred form, the collar simultaneously seals, rotates,
A seal consisting of an annular groove communicating with the air supply on the one hand and the said chamber on the other hand, separated by a friction ring, in order to ensure that the clamping and unclamping movements can be carried out in a programmed manner. The position of the collar with respect to the zero indexing table which is the carrier collar may be fixed, and the axis of the chuck and the device is 1.
/100 mm or less, the centering part is coaxially aligned with the rotation axis of the work table.

The device according to the invention further has the feature that it can be formed, for the most part, by parts that are rotationally fitted into each other rather than threadedly fitted.

The device can be used with conventional chucks, such as F or W types. The accompanying drawings illustrate exemplary embodiments of the invention.

See drawing.

The device consists of cylindrical bores of increasing diameter 26.27.2
It consists of a frame 1 consisting of 8 cylindrical bodies. A part 16 is fitted therein for centering the device and is extended upwardly by a cylindrical sleeve 29 to form the bore 2.
The largest diameter bore 28 forms an annular chamber together with 7.
is machined at the bottom. The sleeve 29 has a cylindrical bore that tapers at the top towards the bottom and is extended below a portion of the taper by a cylindrical bore of slightly larger diameter.

A conical cylindrical sleeve 18 which is divided into two parts and has an externally threaded bushing 19 pushed into the sleeve 16 is housed in the upper part of the sleeve 29. and the pusher 19 surrounds the chuck which is centered and clamped by the conical cylindrical sleeve 18 as the pusher 19 pushes the conical cylindrical sleeve 18 upwardly.

Pusher 19 has a double bore. In the lower bore, the chuck retraction components become adjacent 0
The indexing plate 20 is fixed at 19 to hold it in place 7. The action of the bin 22 allows 19 to be rotated. The centering part 16 is extended towards the bottom by a lower cylindrical sleeve 25 which can pass through the axis of the indexing table.

In said annular chamber, two seals 8 and 8°
and the inner wall of the annular chamber constituted by the sleeve 29 and the cylindrical wall of the fastening part 11, which is held by a circular clip 12 and provided by two seals 13 and 13', separating the annular chamber into two parts. A primary piston is housed provided with a third seal 10 ensuring a tight seal between the pistons. In the upper part of the annular chamber, two seals 15 and 15° and a third seal and an O-ring 1
The purpose of the seals 8.8°, 13.13° and 13'' is to ensure a tight seal with respect to the control compressed air, and the seals 10. 15, and the purpose of 15° is to ensure a tight seal with respect to the oil in the hydraulic chamber 31/32.The frame 1 has a seal carrying collar 2.
is surrounded at its base by. The seal carry collar has two annular grooves 30 and 30' therein communicating with air inlets 24 and 23, respectively. Each of these two banks is, for example, RILSAN.
(registered trademark name) or three sealing grooves 17.1 for receiving friction rings made of stacked carbon fibers or o-rings.
7', and 17". According to an alternative configuration, these grooves can also be provided on the frame 1, in which case the collar 2 is connected to the air supply. It has a radial passage.

Compressed air for clamping is supplied to an inlet 24 provided with a quick release connection, where compressed air for unclamping is supplied by a similar inlet 23. Inlet port 2
4 is connected by a passage 2 to a primary air chamber 33 provided at the rear of the primary piston 4. Intake port 23
are connected by passages 25 to two secondary air chambers, one 34 located in front of the primary piston and the other 35 located in front of the secondary piston.

During installation, the secondary piston 9, fixed intermediate part 11,
The primary piston 4 and then the centering part 16 are introduced in sequence. The oil is introduced laterally through the duct, which is then closed with a threaded plug.

The end of the secondary piston 9 has an internal conical surface that interacts with the conical jaw of the chuck 3.

On the other hand, the outer end of the secondary piston 9 is connected to the frame 1
It has a cylindrical surface 9b that is guided and supports a cylindrical passageway. The chuck 3 is held axially within its housing by its upper part of the cylinder 9. The chuck is guided in its lower part of the conical cylindrical sleeve 18;
Then it is clamped.

The frame 1 is composed of three passages 40 (FIGS. 2 and 3) through which the frame 1 can be screwed onto the working table, from the direction of the arrow F (FIG. 4). A component 6 with visible slots is screwed onto the seal carrying collar 2 (FIG. 2). A threaded bolt on the edge of the indexing frame engages this slot and positions the collar for opening and closing.

The pneumatic hydraulic system functions as follows.

The introduction of compressed air into the primary chamber 33 pushes the primary piston 4 upward. This primary piston, by virtue of its relatively small cross-section end, generates pressure in the oil chamber 31/32. This pressure acts on a substantially larger cross section of the secondary piston 9 which doubles the force of the primary piston.

The secondary piston is in turn actuated by its conical portion 9a on the chuck 3, compressed air is sent into the secondary air chambers 34 and 35 to unclamp the chuck, and the This air acting on the cross-section causes the two pistons to move back in each case and release the chuck.

In order to reduce the size of the unit, in particular to reduce the upper diameter of the device, the frame 1 is arranged in stages (Fig. 1, Fig. 2,
and the material at the top of the frame 1 is cut out so as to have a
by laser or milling), and
The upper part of the piston 9 may extend so as to protrude from the top of the frame; the collar 2 may be partially milled for mounting on multiple indexing tables; the device according to the invention has a small volume; allows precise movement and clamping force of the chuck, and to the machine tool,
It turns out that it constitutes a special, compact, and robust unit that can be especially easily attached to an indexing table.

[Brief explanation of drawings]

Figure 1 is an axial sectional view taken along A-A in Figure 2, Figure 2 is a plan view thereof, Figure 3 is a partial axial sectional view taken along A-A in Figure 2, and Figure 4 is an index. FIG. 3 is a partial side view in the direction of the arrow in FIG. 2 showing the pins that lock the device on the table; 1 frame, 2 seal carrier colors, 3 chucks,
4 primary piston, 8.8' seal, 9 secondary piston, 1
0 Third seal, 11 Fixed parts, 12 Circular clip, 13
．． 13' seal, 13'' O-ring, 15.15' seal, 16 centering part, 18 conical cylindrical sleeve, 19 butcher 20 indexing plate, 22 bottle, 23.24 machine air intake, 25 lower cylindrical sleeve, 26.27.2
8 bore 16 parts, 29 cylindrical sleeve, 30.30
'Annular pipe, 31.32 hydraulic chamber, 33 primary air chamber, 34.35 secondary air chamber, 37 duct, 38 threaded plug, 40 passage.

Claims (1)

[Claims] 1. A rotary pneumatic-hydraulic clamping device for a workpiece on a machine tool, especially on an indexing table, which includes a cylindrical frame (1
), a primary piston (4) which is pneumatically driven in both directions and acts hydraulically on a secondary piston (9) driving the chuck, such that these pistons constitute a force multiplier. consisting of a cross-sectional area ratio of Annular chamber, primary air chamber at the rear of the primary piston (
33), and two secondary air chambers, one in front of the primary piston (34) and the other (35) in front of the secondary piston, the frame of this device ( 1) is mounted in the collar (2) so as to be able to rotate within the collar (2) and is connected to an air supply (23, 24) provided on the collar (2) on the one hand and to the air supply (23, 24) on the other hand. Chamber (33, 34, 3
5) and pneumatic communication means which are in communication regardless of the angle of rotation of the frame (1) with respect to its collar (2). 2. The annular chamber is divided into two parts with different outer diameters, the primary piston being housed in the large diameter part, and the secondary piston being housed in the small diameter part. The device described in. 3. The pneumatic communication means is connected to the frame (1) within the collar (2).
) in which a friction ring is arranged to rotate the sealing groove (17,
annular grooves (30, 30'') separated by
3. Device according to claim 1 or 2, characterized in that it consists of the following. 4. Device according to any of claims 1 and 2, characterized in that said grooves (30, 30', 17, 17', 17'') are arranged on a collar (2). 5. Device according to any of claims 1 and 2, characterized in that the grooves (30, 30', 17, 17', 17'') are arranged on the frame (1). 6. The device is characterized by being composed of a chuck (3) that is installed so that it is in a straight line, a frame (1), and a centering unit (16, 118, 19) that allows the axis of rotation of the indexing table to be obtained. 6. A device according to any one of claims 1, 2, 3, 4, and 5. 7. Device according to claim 6, characterized in that the centering unit consists of clamping subunits (18, 19) capable of clamping the chuck (3) simultaneously with centering. 8. The collar (2) carries means (6) for fixing the position and locking the rotation of said collar of the indexing table, said means (6) carrying a corresponding means (5) carried by said indexing table. Claims 1 and 2, characterized in that they mesh with each other.
8. The device according to any one of 3, 4, 5, 6 and 7. 9. Claims 1, 2, 3, 4, 5, 6, 7, and 7, wherein the frame is machined such that the diameter at its top portion is substantially smaller than the diameter at its central portion. 8. The device according to any one of 8.