JPS60228008A - Clamping device for tool - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention Technical Field The present invention relates to a tool tightening device in which a collet for receiving a tool shaft portion provided with a presser screw can be attached to the front portion g of a chuck in a shape-restricted manner and in a removable manner. Regarding.

BACKGROUND OF THE INVENTION Mechanical tightening devices are known for tightening tools such as drilling tools, milling cutters, and cutting tools having cylindrical shafts. In this type of mechanical loading device, the shank of the tool to be clamped is inserted into a collet provided with an axially extending slit and clamped. Tightening is performed using a cap screw provided on the collet. A cap screw is removably coupled to the collet and is attached to the front portion of the chuck by axial threads. The tightening of the collet is caused by the conical slope when attaching the cap screw to the chuck. This conical slope is formed around the fret and in the insertion hole of the front part of the chuck as follows, that is, when installing the presser screw, the pressure component in the radial direction is applied to the tool shaft to be tightened, which is provided with a slit. It is formed so as to be pressed against the part.

A mechanically acting collet with a cap screw of this kind has the disadvantage that when installing the cap screw, a defined and precise tightening force does not occur.

Fixation by tightening is usually carried out manually using mechanical aids, such as, for example, a key spanner that engages in a recess in the cap screw. However, in reality, in order to firmly fix the cap screw, it is necessary to hit the cap screw with a hammer and rotate it to the final tightening position. in this way,
If a collet with a cap screw is to be installed by hand, the individual tightenings in each case do not necessarily result in a precisely predetermined predetermined tightening force. Furthermore, the magnitude of the tightening force depends on the thread pitch, and therefore threads with the smallest possible pitch are used.
Another drawback is that it takes a relatively long time to install the cap screw. It is also a disadvantage that a part of the force of the generated tightening is lost in the thread of the cap screw or as a frictional force inside the conical contact surface.

Known hydraulic fastening devices with pressure media such as oils, greases, etc. overcome the above-mentioned drawbacks.

In hydraulic clamping devices of this type, a piston with a stroke limiter is actuated via a manually adjustable clamping screw arranged transversely to the axis of the chuck in the front part of the chuck. Thereby, the hydraulically acting oil is distributed in the chamber mechanism and forced against a thin-walled malleable bushing made of special high-speed steel. This malleable bushing is surrounded by a pressure medium over its entire length, so that it can be pressed or rotated uniformly cylindrically and concentrically with respect to the central axis of the chuck. . Furthermore, the malleable bushing is connected firmly and fluid-tightly to the front part of the chuck at both ends. An adjustable vertical stop, which is likewise provided in the front part of the chuck, allows the length of the clamping to be varied. To relieve the pressure, tightening is done by manually rotating the shaft in the opposite direction. This causes a pressure drop in the hydraulic chamber arrangement, so that the malleable bushing returns to its starting position and the clamped tool shank and thus the tool become free.

However, this type of hydraulic tightening device has the disadvantage that the tolerance range is very narrow. Therefore, a tightening device suitable for each diameter of a typical tool requires a device in each case, so that, for example, 1011rlRs '121111.
Clamps of various sizes, such as 0, 25 and 321 m, are adapted exactly to the diameter, respectively, and the aforementioned clamps are special clamps consisting of chucks with elements, which are made using tools. all required. Known hydraulic tightening devices of this type are difficult to use because of these small tolerances, special tightening requires a large number of tools, and therefore, although the tightening is accurate and easy to operate, special tightening requires a large number of tools. Requires a large and expensive support mechanism.

OBJECTIVES The present invention provides that hydraulic clamping devices have a large tolerance range and therefore retain the advantages of mechanical collets with a simple support mechanism, while also eliminating the disadvantages of such mechanical collets. , that is, the force of the tightening is insufficient, and the predetermined tightening force is not accurate. The object is to provide a tightening device which does not have the advantages of a hydraulic tightening device and which advantages are combined with the advantages of a hydraulic tightening device.

Structure In order to achieve the above object, the present invention is characterized in that a clamping means operated by hydraulic pressure is provided for elastically changing the collet to bring the collet into a clamping position. be.

According to a simple embodiment of the invention, the front part of the chuck is provided with a stop for the cap screw of the collet, which collet determines the end position of the cap screw when it is installed. , in which case the cap screw is provided in such a way that it can be installed by hand. This is made possible simply because the outer periphery of the cap screw is provided with a rim or the like. Moreover, such a rim or the like is provided in such a way that it is not necessary to use mechanical aids such as a key spanner or a hammer to tighten the cap screw.

According to a simple embodiment of the invention, at least one clamping means is provided between the collet with the slit and the front part of the chuck, which is biased by a pressure medium.
In particular, the clamping is provided in the form of a sleeve. In this case, the tightening is done by the force of the sleeve, which is arranged between the collet with a slit into which the tool shaft is inserted and the inner wall of the front part of the chuck, as follows: It is advantageous for the collet located in the collet to be displaceable in the axial direction under the action of hydraulic pressure or a similar force.

According to another embodiment, the clamping is done so that when the sleeve moves under the action of hydraulic pressure, a sufficiently large clamping force is generated on the inserted tool shank. The clamping is such that the inner wall of the sleeve and the inner wall of the sleeve form a conical shape with respect to each other, that is, the clamping is exerted by a pressure component acting on the collet in the radial direction when the sleeve moves toward the feeding hole of the collet. is formed.

Tightening is done to allow axial movement of the sleeve.
A hydraulic chamber system is provided having a hydraulically energized pressure piston. The pressure piston is hydraulically connected to an adjusting piston located in another pressure chamber. Because the pressure chamber is formed small,
With only a slight movement of the adjusting piston, the hydraulic pressure in the chamber system increases until a predetermined force is generated on the pressure piston, which eliminates the tightening movement of the sleeve.

According to a practical embodiment of the present invention with a simple configuration, a collet;
The clamping sleeve, the pressure piston for displacing the sleeve, and the pressure chamber are arranged in a recess in the center of the front part of the chuck.

In this case, it is advantageous for the collet to be rigidly and removably connected to the cap screw, for example via an intermediate ring, by means of simple fastening means or by means of a suitable plug. The collet can be fastened to the front part of the chuck together with the cap screw at a fixed stop position.

According to another embodiment of the invention, the precise tightening required can be achieved by connecting one of the pressure chambers of the hydraulic system to the other so that the operator can easily check from the outside whether pressure has developed. The pressure chambers are hydraulically connected. This other pressure chamber is likewise provided with a moving piston, which, when a predetermined working pressure is reached, is marked with a special marking that is clearly visible from the outside under the action of hydraulic pressure. Move to the specified display position. In particular, the piston with the markings and the manually adjustable piston for creating the required tightening pressure are arranged in a common plane, in particular radially or obliquely to the axis of the chuck. Advantageously, the arrangement is such that the

According to another embodiment of the invention, the mechanically operable tightening device is provided with a return device for the sleeve, so that the tightening device can return the sleeve to its return position after the completion of the process. is provided.

This return device has a loosening screw that is adjustable in position in a transverse hole in the front part of the chuck, and the loosening screw is tightened by an axial adjustment force component via an intermediate member such as a ball. Advantageously, the attachment acts on a portion of the sleeve, for example on the four edges.

Advantageous Effects According to the invention, hydraulic clamping has a large tolerance range compared to devices, and thus the advantages of mechanical collets with a simple support mechanism are retained; The disadvantages of the conventional collet, namely, that the magnitude of the tightening force is insufficient, and that the predetermined tightening force cannot be accurately obtained are eliminated.

Embodiment Next, one embodiment of the present invention will be described with reference to the accompanying drawings.

A chuck 2 having a known basic structure is clamped onto a rotating work shaft 2 1, such as a polling spindle or a milling spindle, which is shown diagrammatically in FIG. The chuck 2 has a front f! which is provided with a receiving space on the side opposite to the position for tightening with the work spindle for tightening a shaft 6 of a working tool such as a drilling tool or a milling cutter (not shown in detail).
It has A part 3. In the row of figures, the inner surface 3' of the receiving space is cylindrical. The front periphery of the front part 3 is provided with an external thread 7, the end of which is designed as a radially extending end 7' for fastening the cap screw 5.

The cap screw 5 is connected to a retaining ring 5' which receives the front part of the collet 4.

The collet 4 has a slit 4 extending in the axial direction as usual.
' and has a preferably cylindrical inner wall 4' adapted to the outer circumference of the tool shank 6. The outer periphery of the collet 4 is formed into a conical shape so as to expand in the direction of the arrow 19, that is, in the direction of the inlet hole of the collet. The collet 4, the retaining ring 5' and the cap screw 5 are therefore located at the end portion of the tool shaft 6 and form what is generally referred to as a collet section as a whole. This collet part is easily interchangeable with collet parts of other sizes.

The outer peripheral surface of the cap screw 5 is free from the tool gripping hole and has a rim or a rim so that it can be attached together with the collet 4 to the screw 7 of the front part 3 of the chuck 2, preferably by hand, by the operator. It only has something similar to this. Instead of the axial screw 7 shown in the exemplary embodiments, other form-locking coupling elements can also be provided, such as plugs with suitable stops, linkage elements, etc.

What is important is that the screw fastening of the parts 4, 5, 5' is carried out mostly by hand, and by movement up to the stop provided by the end 7'. Thereby, the operator can fix the fret 4 together with the cap screw 5 by simply moving it to the stop 7' provided by the end of the screw 7, and in this case, the operator can also fix the collet 4 via the cap screw 5. The original tightening force is not affected, and therefore the fixed tightening of the tool shaft portion 6 is not affected.

Collet 4 with slit and front g part 3 of chuck 2
A tightening sleeve 21 is provided between the two. For tightening, the inner wall 21b of the sleeve 21 corresponds exactly to the conical shape of the outer circumferential surface of the collet 4, and for tightening, the outer circumference zza of the sleeve 21 corresponds to the receiving space of the front part 3 of the chuck 2. It is formed into a cylindrical shape corresponding to the inner periphery of.

The tightening sleeve 21 provided according to the invention is
It is arranged in the front part 3 so as to be movable in the axial direction relative to the collet 4. For this purpose, the front part 3 of the chuck 2 is provided with a radially or obliquely extending hole 8,
At this 68, an adjusting piston 9 of the hydraulic tightening mechanism is supported.

The adjusting piston 9 rests outwardly against a threaded pin 0, which is guided in a threaded part 11 of the chuck front part 3 in an adjustable manner.

A gasket 12 is provided on the other side of the adjusting piston 9. The gasket 12 is made of rubber or the like, and seals against the piston 9 a pressure medium chamber 13 containing a hydraulic pressure medium such as oil or fat. The pressure medium chamber 13 is connected to a pressure chamber 15 located concentrically with respect to the axis 2' of the chuck via an axially extending hole 14 or the like. Within this pressure chamber 15, an axially movable pressure piston 16 is supported so as to be able to reciprocate.

The pressure piston 16 is activated by the pressure piston 18.
, and on the forward side in the direction of the arrow 19, i.e. in the feed direction, an end ridge 20
' has a peripheral portion 20 which abuts against the rear end ridge of the sleeve 21.

As already mentioned, the inner side of the sleeve 2J has a conical shape corresponding to the outer circumference of the collet 4, so that when the pressure piston 16 moves in the axial direction, the tightening means that the sleeve 21 moves in the direction of the arrow. When moving in the direction 19, pressure is applied in the radial direction to the collet 4 provided with the slit, and this pressure generates tightening pressure on the shaft W156 of the power tool inserted into the collet 4. .

In order to tighten the tool shank 6, the collet 4 is first attached to the end of the tool shank 6 by means of a cap screw 5, then inserted into the chuck 2, and the cap screw 5 is attached to the front of the chuck 2. It is fixed to the chuck 2 by fastening to the external thread 7 of the part 3. In this case, the cap screw 5 is simply screwed in and fastened by hand, without the use of any tools, up to the end 7' of the screw 7. In this end position of the cap screw 5, which is limited by the stop, the tool reaches its final, precise working position with its shank 6. At this point, the actual tightening of the tool is carried out simply as follows. That is, for example, inserting a socket cap screw (
A threaded bottle 10, which can be formed as a threaded sleeve, is screwed into the threaded sleeve;
This displaces the adjusting piston 9 forward and creates an appropriate hydraulic pressure in the communicating chamber 13.14°15.
This pressure causes the pressure piston 16 (working piston) to move forward in the direction of arrow ]9 by means of its barb 20. In this case, the end surface 20 of the boxwood 20
1, the sleeve 21 is likewise moved forward. In this case, as already explained, the inner surface of the sleeve 21 is formed in a conical shape, and the outer surface of the sleeve 21 is conical, so that the inner surface of the sleeve 21 is formed in a conical shape, and the outer surface of the sleeve 21 is conical. 21 is radially compressed and the tool shank 6 is tightly clamped within the chuck 2.

Furthermore, in the configuration of the invention, the chuck 2 is provided with an indicator for indicating the tightening force that has occurred. This display device has a further pressure chamber 22 which lies in the same radial plane as the screw pin 10 and the pressure piston 9 and is connected to the pressure medium chamber 13. Inside the pressure chamber 22 is a piston 2 equipped with a boxwood 23'.
3 is supported by a spring 28. When pressure is applied, the piston 23 is pulled out of the bore 1 against the force of said spring 28, which is supported in the front part 3 by a screw 29, and is provided with a mark at its end. As a result, when the predetermined hydraulic pressure is reached, the mark on the piston 23 pops out, and the generated tightening pressure is reliably displayed. Therefore, the indication is ensured regardless of the previous state of adjustment of the collet 4, and the operator is informed that the required tightening force has been created in the system.

To remove a tool such as a drilling tool, first remove the screw bottle 1.
0 is rotated in the opposite direction, ie radially outward. The hydraulic pressure in the system is then reduced, thereby reducing the pressure loading of the clamping collet 4 and clamping sleeve 21. The tightening allows the sleeve 21 to return to its starting position.

For this purpose, a loosening screw 24 is provided. This loosening screw 24 is provided in the front part 3 in a hole 17 provided with a screw 27 and via a ball 25 the tightening is applied to the sleeve 2.
1 into the annularly formed recess 26 and tightening causes the sleeve 21 to move axially in the direction opposite to the arrow 19 as follows. That is, the collet 4 is freed and moved so that the tool shaft 6 can be replaced together with the collet 4, retaining ring 5', and cap screw 5.

The advantage of the design according to the invention is that the simply constructed and mechanically acting cylindrical collet together with the cap screw can be easily replaced in a simple manner, thus making it possible to replace this mechanical collet with The desired wide tolerance range is maintained. - 10,000, since the tightening does not require the force to be generated manually via the cap screw of the fret, the generation of undesired tightening forces and therefore inaccurate tightening forces is avoided. The clamping force is obtained via the hydraulic clamping system in precisely the predetermined thickness, which makes it possible to avoid mistakes when applying the clamping force. Also, the fret cap screw is
When installing the cap screw, the tightening force is transmitted through the cap screw, since the manually operated clamp does not have an engagement means for the tool. It cannot be generated manually. According to the invention, it is also possible to use interchangeable frets known per se, ie collets with a cap screw.

The force can be generated hydraulically for a predetermined and precise tightening, and this force can be clearly seen and controlled by means of a display, so that the tool always maintains a predetermined tightening force. It is tightened with. Furthermore, the force of hydraulic clamping is many times greater than that of mechanical clamping devices. Finally, since the force is obtained by hydraulic pistons and cylinders, the clamping is caused by the force being transmitted through the threads, as in the case of conventional mechanical collets. , or the tightening caused due to the conical shape, no loss of force occurs. Overall, the present invention significantly improves the rotational conditions of a tightening device compared to a mechanical tightening device. This is because, in the embodiment according to the invention, the tightening forces are directed primarily in the axial direction. The device according to the invention is easy to operate since it does not require any manual manipulation with conventional collets with cap screws and therefore there is no risk of injury to the operator.

Since several collets with cap screws can be used and replaced, the support device also has significantly reduced clamping compared to conventional, mostly hydraulically operated devices. At the same time, there is an advantage that the tightening range is significantly larger than in the case of a device that performs tightening exclusively using hydraulic pressure. Finally, the tightening and release of the device is also significantly simplified. This is because, in order to release, it is only necessary to adjust the screw pin 10 or the loosening screw 24 in the radial direction. In terms of working technology, the following major advantages are obtained. In other words, with the device according to the invention, a working tool such as a milling cutter, a drilling tool, etc. remains in a predetermined working position precisely adjusted in advance, both during the tightening process and even after the tightening process has ended. Such precise holding is not possible with mechanical collets. This is because when manually tightening the cap screw, the collet may be displaced in the axial direction, making it necessary to readjust the power tool to the correct working position.

In contrast, in the device according to the invention, fret 4 is
After being inserted into the chuck 2 by the operator and occupying the final position, it remains immovable relative to the chuck 2, and the tightening force is applied by the hydraulic piston 6, which is movable in the axial direction. The sleeve 21 is used for tightening that moves in the axial direction.
occurs through. As a result, no change in the position of the tool occurs.

Finally, the front part of the collet 4, which projects beyond the front part 3 of the chuck 2, instead of having a square shape, can have a rounded shape, so that the forces in this area are This change is advantageous, and it is possible to compensate for thread errors between the threads of the holding screw and the threads 7.

[Brief explanation of drawings]

FIG. 1 is a side view of the tightening device according to the present invention, showing the lower part in cross section, FIG. 2 is a sectional view taken along the line n--■ in FIG. 1, and FIG. FIG. ]...Work spindle, 2...Chuck, 3...
Front part of chuck, 4...collet, 5...pressing screw, 7'...stopping part, 9...adjusting piston, 21.
...Tightening sleeve procedure amendment May 29, 1985 Director General of the Patent Office Manabu Shiga l Indication of the case 1985 Patent application No. 71317 2 Name of the invention Tool tightening device 3 Person making the amendment Gesellschaft Mituto Beschlenkterhufsung 4 Agent address: 2-32-4 Nishi-Shinbashi, Minato-ku, Tokyo Patent applicant section of Kaji Kogyo Building application form, drawings, power of attorney and priority certificate 7, contents of amendments

Claims (1)

[Claims] (1) A tool tightening device in which a collet for receiving a tool shaft provided with a presser screw can be removably attached to the front part of a chuck in a shape-restricted manner. ,
A device characterized in that hydraulically actuated clamping means are provided for elastically changing the collet (4) into a clamping position. (2) The front part (3) of the chuck (2) is provided with a stop (7) for the presser screw (5) of the fret (4), and the presser screw (5) can be attached by hand. 2. Device according to claim 1, characterized in that it has, for example, a border on its surface so as to be able to do so. (3) The front part of the collet (4) and chuck (2) (
3), at least one clamping means (21) is provided which is activated by a pressure medium. An apparatus according to claim 1 or 2, characterized in that: (4) The tightening means is arranged between the collet (4) and the inner wall of the front part (3) and supported so as to be movable in the axial direction with respect to the collet (4) in the terminal state. 4. Device according to claim 1, characterized in that the fastener is a sleeve (2]). (5) The outer surface of the collet (4) and the tightening are connected to the sleeve (21
) and the inner wall (21b) are formed conically in the following way, that is, when the collet (4) is tightened when the sleeve 7' (2) moves toward the feeding hole of the fret. Claim 1, characterized in that the device is configured such that tightening is possible by a pressure component acting in a radial direction.
Apparatus according to any one of clauses 4 to 4. (6) To tighten, the sleeve (21) moves in the axial and linear directions using a pressure piston (
16), and is operatively connected to the pressure chamber (]5) of the pressure piston.
6. Device according to claim 1, characterized in that the adjusting piston (9) is hydraulically connected to the adjusting piston (9). (7) A pressure piston (16), a pressure chamber (15),
Claim 1, characterized in that the collet (4) and the clamping sleeve (21) are arranged in a recess in the center of the front part [3] of the chuck (2). 7. The device according to any one of items 6 to 6. (8) An adjusting piston (9) comprising a pressure chamber (15) and a threaded pin (10) is arranged transversely to the axis (2) of the chuck (2), the pressure chambers (13, 15> The device according to any one of claims 1 to 7, characterized in that it is connected via an axially extending hole (14). , ring-shaped 7-gutskin (
]8) to the front part (3) of the chuck (2) and the pressure piston (J6)
has a projecting peripheral part (2o), the end edge (20') of which is in abutment against the adjacent end edge of the sleeve (21). Range 1
Apparatus according to any one of clauses 8 to 8. (10) One of the pressure chambers (13, 15) and the other pressure chamber (2
2) are hydraulically coupled, and the pressure chamber (22) of the above-mentioned
Any one of claims 1 to 9, characterized in that the piston (23) is arranged movably so as to occupy an indicating position when a predetermined tightening pressure is reached. The device described in. (11) The piston (23) with the mark and the adjusting piston (color) are in a common plane and the axis (2) of the chuck (2)
11. Device according to claim 1, characterized in that it is arranged transversely to the device. (12) The tightening is characterized in that a mechanically operable return device (z4.25, 26) is provided for the sleeve (21). The device according to any one of. (13) The return device is located at the front portion (3) of the chuck (2).
has a loosening screw (24) adjustable in position supported in a lateral hole (17) of the ball (25);
) etc., the axial force component acts on the edge of the recess (26) of the sleeve (21) in the following manner, i.e., the tightening occurs when the loosening screw (24) is rotated. 13. The sleeve (21) acts in such a way that the sleeve (21) can be returned to its starting position in a direction opposite to the direction of the feed hole of the collet. The device described in.