DE2512227A1 - EXPANDING THORN - Google Patents

Description

Expanding mandrel

The invention relates to an expanding mandrel which, by means of the action of a spring plate, tensions and thereby an accurate and reliable processing.

Thorns are known which utilize the tensioning effect of a spring plate (membrane); deformed an actuation axial force the spring plate carrying the jaws resiliently so that the workpiece to be machined between the extended Jaws can be introduced, the subsequent clamping of the workpiece by tilting the jaws goes on during the return of the spring plate to its starting position after the actuation force has been released. In the known thorns, the spring plate or membrane is generally in the form of a disk or one Plate of constant thickness on which the jaws or the jaw carriers are directly mounted; or jaw carriers, for example with dovetail formations that extend radially

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extend and allow the attachment of the jaws for clamping workpieces of different diameters, form a part with the spring plate. The known spring plates are stiff at their circumference on the housing of the mandrel, generally attached by means of claws which have a thickness less than that of the disc or plate.

These known mandrels suffer from a large number of disadvantages. The use of a single rigid arrangement consisting of spring plate jaw (or spring plate jaw support jaw ) leads to reliability and sufficient accuracy when clamping of the workpieces. The spring plate works together with the jaws (or jaw carriers) and is therefore in acted irregularly over the entirety of its area. The possible increase in the number of work cycles and, if necessary, the temperature changes on the mandrel due to its work rhythm allow the determination, that the clamping force of these known mandrels varies from one clamping process to another. Otherwise bulges the spring plate, which has a constant thickness, as it is elastically deformed outward; and the generating its surface, which is arranged against the workpiece and carries the jaws, becomes a curve that is more indefinite Shape. The force then exerted on the fastenings of the jaw and thus on the spring plate is irregular.

On the other hand, the rigid attachment to the housing of the spring plate leads to circumferential skewing, which is less Thickness than that of the disc have dangers one

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Tearing or breaking these claws.

The measure according to the invention is intended to remedy these disadvantages by using an expanding mandrel, which by means of the Effect of a spring plate tensions and is of great accuracy and reliability, is proposed and im rest has the advantage of great simplicity, so this should only be a low cost in production bid and be easy to maintain; Such a mandrel should also be designed so that it is easier and safer Way to clamp workpieces of different diameters and dimensions without changing the Spring plate or even the jaw carrier can be used.

To solve this problem, the invention proposes an expanding mandrel with a spring plate, jaws and jaw carriers, which is characterized by the fact that the jaw carriers are designed to bind independently and sit firmly without play this spring plate support} that connecting devices are provided between the membrane and Irägerplatten and a Play between the spring plate and these connecting devices is provided that the jaws are radially adjustable or are designed to be adjustable in these jaw carriers for clamping workpieces of different dimensions and that actuating devices are provided which act axially in order to elastically deform this membrane and to tilt the jaw carrier and the jaws associated therewith, in such a way that the insertion or withdrawal of the workpiece to be machined or the machined workpiece becomes possible, with a game between these controls and the spring plate or

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- 4 membrane is present.

According to a preferred embodiment of the invention, the Peder plate is made so that the generatrix your coming into contact with the bearers! 'laugh a straight line remains whether the leather panel is elastic is deformed or not.

For further advantages and features of the invention, see from the following description of examples such a Hornss

shows a fountain according to the invention in Cut for clamping workpieces from outside |

shows a side view of the attachment the jaw support on the membrane}

Pig. 3 shows a TTerwirlcliohungsform the storage of the jaws on the jaw carrier j

Pig. FIGS. 4 and 5 show another embodiment of FIG

Attachment of the jaws on the jaw carrier

Pig. β shows a mandrel Jüaeh of the invention, the is designed for clamping workpieces from the inside (bore) j and

Pig. 7 shows in section an embodiment of FIG Peder plate (membrane).

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Reference is first made to the embodiment of Pig. I to 3.

The basic body 1 is designed so that it is centering of the mandrel on the spindle of the machine and is able to carry all functional organs and elements of the spine.

The actuating clamping member of the workpiece P "consists of a spring plate 2, which is made, for example, in the form of an elastic disc made of steel. This spring plate 2 is held in its position with respect to the body 1 by its circumference between the body 1 and one on the body . secured via screws 4 ring rim 3 is enclosed at least three jaw carrier 5 manufactured in the form of an L-shaped salvation support with one of its legs 5p ^au ^ the side AV of the membrane 2 (see Fig. 7) from the other limb 5-. | the jaw carrier 5 carries the jaw 10, the radial position of which is adjustable as set out below, the axis y-y of each jaw running parallel to the surface AV of the spring plate in the clamping position.

Each jaw carrier 5 is connected to the spring plate 2 by means of a screw 6 which is screwed into a cap 5 ~ of the jaw carrier 5. A small working cycle remains between the rod 6 of the screw and the membrane at the location of the opening cut out in this, in order to enable this rod 6 ... to pass through; the head 6 _{2 of} the screw 6 is supported on the surface AR of the spring plate 2 (see Fig. 7). In the middle of the mandrel the end of the leg 5 ₂ cLes beacon carrier 5 is formed by a flat part 5 ^> whose back is fixed

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supported on the surface AV of the spring plate 2 and against the front side of which engages an edge of a heart disk 7, which by means of a screw 9 against the actuator 8 is screwed.

It can be seen that there is a play "j", the so-called "tension play" between the surface AR of the diaphragm 2 and the body 1, which is essentially equal to the play "j-x ¹¹ between the actuating member 8 and the body 1. This Arrangement makes it possible to use the same mandrel for clamping the workpieces from the outside or from the inside (hole).

The jaws IO consist, for example, of a head 10 'and a cylindrical body 10 "provided _{with a flattening 10 1} is worked out, which serves to fix the jaw in the radial and rotational position, as soon as its radial position has been set as a function of the dimensions of the workpiece P. A ring 11 can optionally between the head of the jaw 10 'and the jaw carrier 5 for the case that considerable support forces occur between the head 10 'and the workpiece P during machining.

In another embodiment (Figs. 4 and 5), the body 10 ^f 'of the jaw 10' is threaded (the corresponding hole in the jaw carrier then carries

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Internal thread) and comprises two diametrically opposed flats 1O ₁ 'and 10 ^f ·; the jaw is fixed with the accuracy of a half turn of the body or pin part 10 "by means of a keyway system 12 with an inclined surface 13» which is tightened or loosened via nuts 14, 15 (see also] Pig. 2 and 3). At least three stops 16 are releasably attached to the central part of the body 1 and pass through the spring plate 2 in slots provided for this purpose.

A ring of suitable diameter (not shown) can be attached to these stops 16; this Ring rim has dimensions that allow the positioning of the workpieces P that have a hole, their The inner diameter is too large for the workpiece P to be supported against the stops 16.

The same mandrel with the same jaw carriers also enables the workpieces to be clamped via their bore. It is sufficient for this that the heads 10 'of the jaws 10 are radial are directed outwards and that stops are attached to the body transversely to the ring collar 3.

Fig. 6 shows a mandrel for machining workpieces P ^ clamped in the bore. At least three attacks 17 are attached to the body 1 via the nuts 18 which penetrate the ring collar 3. For example, in Fig. 6 jaw carriers shown have exactly the same essential features as the jaws shown in Fig. 1

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■ "· ■ ^ j * ·· ■ *

carrier 5, however, are insignificant in terms of their shape different.

These essential features of the jaw carriers are the reference surface 5 * 'C 5 1 * ^s in Mg ₃ 6), which interacts with the reference surface 2., ' of the hanging bead 2 .. of the membrane 2 and the slightly curved bump surface ⁵ 4 * ί ⁵¹ 4 * ^ijQ " ¹ S * ^ß )? ^{those with the} heart disc 7 for the process of loosening the fountain znsammenifirk1 ₀

After an essential! ». Feature of the Born to the invention oils generatrix must "remain o" a straight line öei ³ surface && ~ £ spring plate everted against the su machined workpiece b now the spring plate (diaphragm) is deformed (durcli an applied example, in the central iCeil Asialkraft) for loosening or whether it is in the clamping position without deformation, as shown in Ed. 1 and 6 »

According to the invention it has been found that such a spring plate, for example as in Pig. 7 geseigt _s can be realized. The spring plate (diaphragm) 2 consists of an elastic disc, for example made of steel, and comprises an annular bead 2 _1? the underside of which is 2 ^ ³ precision machined. The generating line of the surface AV is a straight line. The generating line of the surface AR of the membrane 2 which is turned against the body of the mandrel is a hyperbola | the axis χ - χ of the membrane is the asymptote. The minimum thickness a on the circumference of the membrane and the maximum thickness l in the central part of the membrane are preferably selected in such a way that the ratio

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b is between 1.5 and 2.5. Here the Aba hang

measurements of a (and b) only from considerations more constructive Type and size of the mandrel, material of the membrane, available and desirable force when loosening, etc.

The operation of the mandrel according to the invention is as follows:

Once the clamping diameter has been determined, the jaws are adjusted and adjusted, the actuator 8 is displaced axially by any known means: by hand, mechanically, hydraulically, pneumatically, electrically; the actuator 8 takes the heart disc or the Throw 7 with; the diaphragm 2, the periphery of which is held with respect to the body 1, is elastically deformed. If the workpiece P is clamped from the outside, the actuating element 8 is acted upon in the direction of the arrow f until the game "j ^? for solving is absorbed. The Membrane 2 bulges outwards and takes the jaw carrier 5 with it via the heart disk or the cover 7 and the ueile 5.; these then lead to a tilting movement at the top around the peripheral part of the enclosed by the rim 3 Membrane 2 off. During this tilting movement, the generating line of the surface AY of the membrane 2 remains a straight line due to the shape of the membrane, however also due to the presence of the small working cycle between the rod 6 ^ of the bolt 6 and the membrane and the small work cycle between membrane 2 and heart disk or cover 7. Since the jaws 10 also after are tilted at the top, the workpiece P to be clamped can be inserted o

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If the axial force on the actuating member 8 is canceled, the membrane 2 returns elastically to its starting position back and takes the jaw carriers and the jaws with and the workpiece P is proportional with a force stretched to the rigidity of the membrane 2.

The clamping movement of the jaw carriers and jaws also means that the workpiece is positioned exactly axially by pressing it firmly against the stops 16.

To clamp the workpieces P .. from the inside it is sufficient, after suitable assembly of the jaw carriers and jaws on the actuator 8 in the direction of arrow f .. until the relaxation play ¹¹ J "is absorbed: the jaw carriers and jaws then tilt inwards for the process of loosening.

This type of mandrel can also be used to machine workpieces that remain immobile: the tool shifts. The shape of the workpiece can then be any.

The mandrels according to the invention can be used for all machining operations, in particular for series production use where the use of a Special tool is not justified. However, the mandrels can also be used on machines with an automatic process sequence Find use.

Expectations

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Claims (10)

- li - CLAIMS 1.) Expanding mandrel, in which under the action of a spring plate or membrane, the workpiece is clamped and this membrane is elastically deformed to loosen it, with jaws and jaw carriers, characterized in that the jaws are designed to be independent of one another and are firmly supported against this .Federplatte without play; that connecting devices between this Membrane and the support jaws are provided, with a play between the membrane and these connecting devices is left; that the jaws are radially adjustable or controllable in these jaw carriers, such that workpieces of different dimensions can be clamped; and that actuators are arranged, which act axially for the elastic deformation of the membrane and the jaw carriers and their associated Let the jaws tilt so that the insertion (or removal) of the or machined workpiece is possible, with a game between these actuators and the Membrane or spring plate is left. 2. Spreidorn according to claim 1, characterized in that the membrane is designed such that the generatrix their surface in contact with the jaw support remains a straight line regardless of whether the membrane is is elastically deformed or not. 3. Expanding mandrel according to claim 2, characterized in that the generatrix of the against the workpiece to be machined facing surface AV of the membrane is a straight line and that - 12 509844/0314 the generatrix of the surface AR of the membrane turned against the body of the mandrel is a hyperbola, the axis the membrane forms the asymptote. 4. expanding mandrel according to claim 3 »characterized in that that the ratio between the maximum Thickness of the membrane of its central part and the minimum Thickness on its circumference is between 1.5 and 2.5. 5. expanding mandrel according to one of the "preceding claims, characterized in that dedicated facilities to determine the membrane catch with respect to the body of the expanding mandrel are provided, 6. expanding mandrel according to one of the preceding claims, characterized by axial stops attached to the body of the mandrel. 7. expanding mandrel according to claim 4 odec claim 6, characterized characterized in that the membrane has an annular bead on its surface AV, one surface of which as To serve the reference surface, is precision machined, wherein the reference surface interacts with a reference surface of the jaw carrier. 8. Expanding mandrel according to one of the preceding claims, characterized in that the actuating devices an actuator (8) which is connected to a working member, and a heart disc or a Have cover (7) to axially the central part of the membrane (2) and the jaw carrier (5, 51) accordingly to take along a game (j, j-j) that causes solving the problem. - 13 509844/0314 9. expanding mandrel according to one of the preceding claims, characterized in that the jaw carrier (5, 51) a G-estalt in the general form of an L, whose one leg is pressed against this membrane (2) and screwed into the jaw support with this by means of a leg Rod (6) is connected, with an operating play remaining between this Rod.und the membrane; and that the other leg comprises a bore for mounting the jaws (10, 100), with devices (12, 13, 14, 15) are provided to fix these jaws in the radial position and rotational position. 10. Expanding mandrel according to claim 9, characterized in that the jaws consist of a head (10 ¹ , 100 ') and a smooth rod with a flat or a threaded rod with two flats "). 5098U / 03U