WO2003087588A1

WO2003087588A1 - Fluid-actuated contraction drive

Info

Publication number: WO2003087588A1
Application number: PCT/EP2003/003511
Authority: WO
Inventors: Bernd Lorenz; Stefan Schwarz
Original assignee: Festo Ag & Co
Priority date: 2002-04-12
Filing date: 2003-04-04
Publication date: 2003-10-23
Also published as: EP1495233A1; DE50303838D1; DE20205655U1; EP1495233B1

Abstract

The invention relates to a fluid-actuated contraction drive. Said drive comprises a contraction tube (2), whose length contracts when an impingement chamber (7) that is delimited by said tube is subjected to the force of a fluid and whose two end regions (5, 6) are respectively equipped with a force tapping unit (8), which allows the generated drive force to be tapped. At least one end region (5, 6) of the contraction tube (2) is flat and is braced between two retaining arms (22, 23) of a fork-type clamping head (18) of the allocated force tapping unit (8), whereby the interior surfaces of the opposing tube wall sections (11a, 11b) are pressed together tightly.

Description

Fl 11 -i riht ---- 1- ä. * - i gter nntra t i on jan ri ph

The invention relates to a fluid-actuated contraction drive with a contraction tube, which at Fluidbeauf- a suppression of him limited Beaufschlagungsräumes a ängenk _^ ntraktion learns and enabling Kraftabgriffseinheit is equipped at its two end regions surfaces each having a the tap of the generated drive force.

WO 00/61952 AI and EP 0161750 B1 each show a fluid-operated contraction drive, which contains a contraction hose, to each of which a force tapping unit is attached at the end. The contraction tube contains a rubber-elastic tube body and a pull-fiber arrangement which is coaxial with respect to it. If the pressure chamber delimited by the contraction tube is filled with fluidic pressure medium under a certain actuation pressure, the contraction tube experiences a radial expansion in connection with an axial contraction in length. As a result, tensile forces are exerted on the force tapping units, so that these are acted upon in the sense of mutual approximation. In this way, external structures and components which are fixed to the force tapping units can be clamped together and / or moved relative to one another.

Especially when a high operating pressure is applied, it is problematic to ensure a secure seal and reliable power transmission to the force tapping units at the end regions of the contraction hose. It is therefore the object of the present invention to provide a fluid-operated contraction drive in which such problems no longer occur or are at least reduced.

This object is achieved in the case of a fluid-operated contraction drive of the type mentioned at the outset in that at least one end region of the contraction hose has a flat shape and is clamped between two holding arms of a fork-like clamping head of the associated force tapping unit, the inner wall surfaces of the opposing hose wall sections being pressed tightly together.

By clamping the flat end region of the contraction tube, a secure connection of the force tapping unit to the contraction tube, which is primarily based on the frictional connection, can be achieved. At the same time, a reliable sealing of the contraction tube is achieved, the inner surfaces of which are firmly compressed under sealing in the area of the clamping point.

Advantageous developments of the invention emerge from the subclaims.

The flat shape of the clamped end region of the contraction tube is expediently based on a compression of the contraction tube, which is hollow as a whole before the force-tapping unit is attached.

The flat shape of the hose end area also has the advantage that the connection area between the contraction hose and the force tapping unit can be implemented in a very flat, compact design.

Although it would be possible in principle to design the two holding arms of the clamping head as independent, firmly connected components, it has proven to be particularly advantageous. partly to provide a one-piece design. This makes the manufacture and assembly particularly easy.

It is also advantageous if, in addition to the clamping fastening, positive fastening measures are provided between the clamping head and the associated end region of the contraction tube. As a result, the tensile forces that can be transmitted from the contraction hose to the force tap unit are particularly high.

To implement positive fastening measures, fasteners can be provided which are fixed to the holding arms and positively engage in the clamped end region of the contraction tube. The fastening means can be at least partially formed by tooth-like projections of the two holding arms which engage at least in the hose wall section of the contraction hose which is directly acted upon. For example, they can be formed in one piece from the material of the holding arms by punching and bending.

Alternatively or additionally, the fastening means can contain at least one fastening bolt fixed to the two holding arms and penetrating the intermediate end section of the contraction tube, for example at least one screw or at least one rivet.

The clamping forces required for clamping the end section can be achieved solely by appropriately pretensioning the holding arms on the basis of their material selection and / or shape. However, there is also the possibility, additionally or alternatively, of prestressing the two holding arms with respect to one another, so that the end region of the contraction tube lying in between is clamped. These clamping means can be formed by the fastening means mentioned above. In a preferred embodiment, the clamping space, which is delimited by the two holding arms and has the flat shape of the end region of the contraction tube, has a front flat clamping section and an eye-like expanded clamping section adjoining it on the rear. In the widened clamping section there is a clamping body which is movable relative to the clamping head and around which the end region of the contraction tube is wrapped with its axially outer end section. With such a design, there is a particularly advantageous self-locking effect when the contraction tube is subjected to internal pressure.

The contraction tube expediently consists of a tube body with rubber-elastic properties, in the wall of which a tensile fiber arrangement is embedded in a coaxial arrangement. The tension fiber arrangement can also sit on the outer circumference of the hose body. The tension fiber arrangement expediently consists of a plurality of tension fibers arranged crosswise with high tensile strength and at the same time bendable properties. The flexibility of the contraction tube at the end area concerned is not hindered due to the flexibility.

If, in addition to the non-positive clamping, form-fitting fastening measures are also provided which have fastening means penetrating into the contraction tube or penetrating the contraction tube, the arrangement is expediently such that the fastening means engage in the tensile fiber arrangement of the contraction tube.

The invention is explained in more detail below with reference to the accompanying drawing. In this show: 1 is a schematic longitudinal sectional view of a preferred first design of the contraction drive according to the invention,

2 to 4 are enlarged, perspective representations of the end section of the contraction drive marked at II in FIG. 1 from different angles,

5 and 6 show an alternative embodiment of the end section II marked in FIG. 1, FIG. 5 showing a perspective view and FIG. 6 showing a longitudinal section according to section line VI-VI from FIG. 5, and

Fig. 7 shows a further alternative embodiment of the end portion of the contraction drive marked II in Fig. 1 in a perspective view.

The drawing shows a fluid-operated contraction drive, generally designated by reference number 1. It can be operated with liquid or, preferably, with a gaseous medium.

An essential component of the contraction drive 1 is a tube-like membrane element, referred to as the contraction tube 2, which essentially consists of a tube body 3 made of rubber-elastic material and a tension fiber arrangement 4 arranged coaxially with the tube body 3. The tensile fiber arrangement 4 could enclose the hose body 3 like a sock. It is preferably embedded in the wall of the hose body, so that it represents a hose-like structural unit with it.

The contraction tube 2 is closed in a fluid-tight manner at its two end regions 5, 6. It limits you hermetically sealed, elongated exposure chamber 7 from the surroundings.

A force tapping unit 8 is attached to each end region 5, 6. This is provided with force tapping means 12, to which structures or components to be moved or braced can be attached directly or indirectly. In the exemplary embodiments, the force tapping means 12 are formed by one or more holes which, for example, permit screw fastening or a hanging device for the components mentioned.

In the deactivated initial state, which is shown in solid lines in FIG. 1, the force tapping units 8 arranged at the two end regions 5, 6 are at a maximum distance from one another. The contraction tube 2 has a certain initial length. The pressurization chamber 7 is depressurized.

To activate the contraction drive 1, the pressurizing chamber 7 is acted upon by fluidic pressure medium which is under a predetermined actuation pressure. This pressure medium can be fed in via a fluid line 13 communicating with the pressurization chamber 7. In the exemplary embodiment, the fluid is fed through the wall of the hose body 3, which is equipped with suitable connection means 14 for this purpose. However, it would also be possible, particularly in the case of a gas-operated contraction drive, to generate the drive gas in the interior of the pressurization chamber 7 by means of a pyrotechnic gas generator (not shown).

When the activation chamber 7 is acted upon by an internal pressure, so that the contraction tube 2 is expanded radially. This radial expansion is accompanied by an axial shortening of the hose length. As a result, the force tapping units 8 are pulled toward one another. The reason for this behavior is the special structure of the contraction tube 2, in particular in connection with the aforementioned tension fiber arrangement 4. In the embodiment, the tension fiber arrangement 4 has a large number of individual tension fibers 4 or strands combined into strands, which assume a crossover configuration. Viewed in the radial direction with respect to the longitudinal axis 15 of the contraction drive 1, the tensile fiber arrangement in particular forms a lattice-like structure. When the radial expansion of the tubular body 3, the grating angle change, so that by the contraction tube 2 at the two end portions 5, 6 a tensile force, we generated ^". This tensile force, whose direction is indicated by arrows 16, is coupled to the force-locking and preferably positively Force tapping units 8 are transmitted, which consequently approach each other in the direction of tensile force 16. The activated state which can be achieved in this way is indicated by dash-dotted lines at 17 in FIG.

The contraction tube 2 could also have a different structure which ensures the described operating behavior.

When actuated, the structures and / or components fixed to the force tapping units 8 are displaced relative to one another, so that the desired action occurs.

The contraction tube 2 is characterized by a special configuration of its two end regions 5, 6 and the force-tapping unit 8 which is fixed thereon. This is explained in more detail below with reference to the end region 5 on the left in FIG. 1, which is shown enlarged in FIGS. 2 to 4. The design at the other end region 6 is expediently identical. However, there is also the possibility of providing different designs at the two end regions. The above as well as the following explanations apply equally to all the embodiment variants shown in the drawing, unless something else is mentioned in individual cases.

The contraction tube 2 has a flat shape at its end region 5. This is achieved, in particular, by compressing a contraction tube 2, which has a hollow cylindrical shape, at this end region 5 from opposite transverse sides, so that diametrically opposed tube wall sections 11a, 11b lie flat and close to one another with their inner surfaces.

The force tap unit 8 contains a force tap part 19, the front area of which, facing the contraction tube 2, forms a fork-shaped clamping head 18. The clamping head 18 has two preferably plate-like holding arms 22, 23, which lie next to one another with mutually parallel expansion planes, wherein they define a clamping gap 24 between them.

The contraction tube 2 engages with its flat shape end region 5 in the clamping intermediate space 24 and is acted upon from opposite sides by the two holding arms 22, 23 and pressed firmly together. In this way, the contraction tube 2 is non-positively clamped in the fork-like clamping head 18 at its end region 5.

The holding arms 22, 23 each act on the hose wall section 11a or 11b assigned to them, which consequently has a flat shape, the hose wall sections 11a, 11b being pressed tightly together with their mutually facing inner surfaces. The resulting sealing area is marked at 25 in FIGS. 3 and 6. Thus, the exposure supply space 7 sealed at the end regions 5, 6 of the contraction tube 2 to the environment.

The two holding arms 22, 23 are expediently formed in one piece with one another. They merge into one another in one piece in a root region, to which is connected a force tapping section 27 which projects axially away from the contraction tube 2 and which is equipped with the force tapping means 12. In all of the exemplary embodiments, the force tapping section 27 is of flat plate-like design and contains one or more holes through it, which form the force tapping means 12.

5 to 7, the non-positive clamping of the end region 5 results solely from the mutual prestressing of the holding arms 22, 23, on the basis of their material selection and the design of the clamping head 18. Without an end region 5 inserted between them, the holding arms 22, 23 take one another approximate starting position. To fix the end region 5, they are briefly spread apart by applying force, so that the wiper space 24 is widened. After the subsequent insertion of the end region 5, the holding arms 22, 23 are released, and because of their need to return to the starting position, they firmly press the end region 5 together. In this connection, the clamping head 18 expediently has spring-elastic properties.

In order to achieve a particularly high clamping force, the two holding arms 22, 23 can additionally be prestressed against the end region 5 of the contraction tube 2 from opposite sides by means of clamping means 28 bridging the clamping intermediate space 24. Such a design is in the embodiment of FIGS. 1 to 4. One or more fastening bolts 32 serve here as clamping means 28, which are fixed with their respective two ends to the holding arms 22, 23 and which are arranged in the clamping intermediate space 24 Push through the end section 5 of the contraction tube 2. They are expediently screws or rivets which rest with their heads on the outside of the respective holding arms 22, 23 facing away from the clamping space 24 and in this way exert the desired clamping force or clamping force on the holding arms 22, 23.

A particularly high level of security against the contraction tube 2 slipping out of the clamping head 8 is achieved by additional positive fastening measures. Such positive fastening measures result in the embodiment of Fig. 1 to 4 of the provided there Cmd Stigungsb ^'lzen 32. penetrate the end portion 5, which has been previously perforated accordingly. Since the tensile fiber arrangement 4 is also penetrated, a particularly secure connection results.

Also in the embodiments of FIGS. 5 and 6, fixed fastening means are provided on the holding arms 22, 23, which engage positively in the clamped end area 5 of the contraction tube 2. They consist here of tooth-like projections 33 which protrude from the inner surface of the respective holding arms 22, 23 facing the clamping intermediate space 24 into the clamping intermediate space 24. As can be seen clearly from FIG. 5, they engage positively into the contraction tube 2. The arrangement is expediently such that the tooth-like projections 33 provided on a respective holding arm 22, 23 only dip into the hose wall section 11a, 11b which is directly acted upon.

The tooth-like projections 33 can in particular be formed from one-piece material components of the holding arms 22, 23 and can be produced in that they are punched out and bent out of this material. The tooth-like projections can be pressed out of the holding arms when the two holding arms are pressed together. Prefers They taper in a wedge shape so that they can reliably penetrate the rubber-elastic tube body material.

In the embodiment of FIG. 7, the clamping space 24 is designed in a very special way. It has on the front axially facing the contraction tube 2 a front flat clamping section 34, to the rear, towards the force tapping section 27, followed by an eye-like expanded clamping section 35. In the widened clamping section 35 there is a preferably cylindrically designed clamping body 36, which is movable relative to the clamping head 18 and consequently also relative to the force tapping part 17 b.

The end section 5 of the contraction tube 2 first penetrates the flat clamping section from the front

34 and lies with its axially outer end section 37 inside the eye-like widened clamping section 35. In this, it is wrapped around the clamping body 36, so that its outer end section 37 is designed like an eye and encloses the clamping body 36 along at least a large part of its circumference , When the contraction tube 2 is subjected to a tensile load, the clamping body 36 is pulled along to a certain extent, so that the clamping section between this clamping body 36 and the eye-like widened portion

35 defining arm section 38 is additionally jammed. One could speak of self-locking here.

In the exemplary embodiment in FIG. 7, the eye-like widened clamping section 35 is largely defined by the design of only one holding arm 22. While the second holding arm 23 has a linear extension, the first holding arm 22 has a bulge or bulge following the root region 36, which defines the eye-like widened clamping section 35 and which is followed by a front section which then again parallel to the second holding arm 23 runs. All of the exemplary embodiments described and the design measures described in connection with them can be combined with one another without further ado.

Adhesive can additionally be applied to the end regions 5, 6 in the interior of the contraction tube 2 in the sealing region 25, so that the inner surfaces are connected to one another particularly intimately.

Claims

Fl ni r-hpl-äl-i gter contract, i nnsantri ph claims

1. Fluid-actuated contraction drive, with a contraction tube (2), which experiences a length contraction when fluid is applied to a chamber (7) that it delimits and which at its two end regions (5, 6) each taps the generated drive force Enabling force tapping unit (8), characterized in that at least one end region (5, 6) of the contraction tube (2) has a flat shape and is clamped between two holding arms (22, 23) of a fork-like clamping head (18) of the associated force tapping unit (8) , the opposite hose wall sections

(lla, llb) are pressed tightly together with their inner surfaces.

2. Contraction drive according to claim 1, characterized in that the contraction hose (2) is a hollow cylindrical contoured structure, the flat shape of its at least one end region (5, 6) being based on the clamping in the fork-like clamping head (18).

3. contraction drive according to claim l or 2, characterized in that the two holding arms (22, 23) of the clamping head (18) are integrally formed with each other.

4. contraction drive according to one of claims 1 to 3, characterized in that the two holding arms (22, 23) have a plate-like shape.

5. Contraction drive according to one of claims 1 to 4, characterized by positive locking measures provided in addition to the clamping between the clamping head (18) and the associated end region (5, 6) of the contraction tube (2).

6. contraction drive according to one of claims 1 to 5, characterized by fastening means (32, 33) which are fixed to the retaining means (22, 2) and positively engage in the clamped end region (5, 6) of the contraction tube (2).

7. contraction drive according to claim 6, characterized in that the fastening means are at least partially formed by tooth-like projections (33) of the holding arms (22, 23).

8. contraction drive according to claim 7, characterized in that the tooth-like projections (33) are punched out and bent out of the material of the holding arms (22, 23).

9. contraction drive according to claim 8, characterized in that the fastening means contain at least one on the two holding arms (22, 23) and the intermediate end section (5, 6) of the contraction hose (2) penetrating fastening bolt (32).

10. contraction drive according to claim 9, characterized in that at least one fastening bolt (32) is formed by a screw or a rivet.

11. Contraction drive according to one of claims 1 to 10, characterized in that the two holding arms (22, 23) delimit a clamping space (24) into which the contraction tube (2) engages with its flat region in the end region (5, 6), the two holding arms (22, 23) being tensioned by means of the clamping means (28) bridging the clamping space (24) are biased from opposite sides against the end region (5) of the contraction tube (2).

12. Contraction drive according to one of claims 1 to 11, characterized in that the two holding arms (22, 23) limit the flat shape end region (5) of the contraction tube (2) receiving the clamping space (24), the front flat clamping section (34) on the side facing the ontrakti-nsschlauch (2) and has an eye-like widened clamping section (35) adjoining it on the back, wherein in the eye-widening clamping section (35) a clamping body (movable relative to the clamping head (18) 36) is arranged around which the end region (5, 6) of the contraction tube (2) is wrapped with its outer end section (37).

13. Contraction drive according to claim 12, characterized in that the clamping body (36) is cylindrical.

14. Contraction drive according to one of claims 1 to 13, characterized in that the contraction hose (2) a hose body (3) consisting of rubber-elastic material and a to the hose body (3) coaxial, expediently embedded in the wall of the hose body (3) tension fiber arrangement ( 4).

15. Contraction drive according to claim 14, characterized in that the tension fiber arrangement (4) has tension fibers arranged in a cross configuration.