EP1495233B1 - Fluid-actuated contraction drive - Google Patents

Description

The invention relates to a fluid-operated contraction drive, with a contraction tube, which undergoes a length contraction upon fluid loading of a limited Beaufschlagungsraumes and which is equipped at its two end regions each with a tap of the generated driving force permitting Kraftabgriffseinheit, wherein at least one end portion of the contraction tube has flat shape and is clamped between two retaining arms of a fork-like clamping head of the associated Kraftabgriffseinheit, wherein the opposite hose wall sections are pressed together with their inner surfaces and wherein fastening means are provided which are fixed to the support arms and engage positively in the clamped end portion of the contraction hose.

WO 00/61952 A1 and EP 0161750 B1 each disclose a fluid-actuated contraction drive which contains a contraction tube to which a respective force-tapping unit is fastened on the front side. The contraction tube includes a rubber elastic tube body and a coaxially with respect to this Zugfaseranordnung. If the pressurization chamber, which is limited by the contraction tube, is filled with fluid pressure medium under a certain actuation pressure, the contraction tube undergoes a radial expansion in conjunction with an axial length contraction. As a result, tensile forces are exerted on the force tapping units, so that they are applied in the sense of mutual rapprochement. In this way, external structures and components, which are fixed to the Kraftabgriffseinheiten, clamped together and / or moved relative to each other.

In GB 932111 A, a contraction drive of the type mentioned is proposed, in which in addition to a Einspannbefestigung positive fastening measures between the clamping head and the associated end portion of the contraction tube are provided. The transferable from the contraction tube to the Kraftabgriffseinheit tensile forces are particularly high. The attachment measures consist of fastening bolts that pass through the contraction tube.

Especially when exposed to high operating pressure, it is problematic to ensure a secure seal and reliable power transmission to the Kraftabgriffseinheiten at the end of the contraction tube.

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 a fluid-operated contraction drive of the type mentioned above in that the fastening means are at least partially formed by tooth-like projections of the two retaining arms.

By clamping the flat end portion of the contraction tube, a traction-based secure Connection of the Kraftabgriffseinheit be accomplished on the contraction tube. At the same time, a reliable sealing of the contraction tube is achieved, the inner surfaces of which are firmly compressed in the region of the clamping point while being sealed. By the tooth-like projections, which engage at least in the immediately applied hose wall portion of the contraction tube, additional positive fastening measures can be realized.

Advantageous developments of the invention will become apparent from the dependent claims.

The flat shape of the clamped end region of the contraction tube is expediently based on a compression of the hollow cylindrical contraction tube which is altogether hollow prior to the attachment of the force tapping unit.

The flat shape of the Schlauchendbereiches also has the advantage that the connection area between the contraction tube and the Kraftabgriffseinheit can be performed in a very flat, compact design overall.

Although it would be possible in principle to perform the two retaining arms of the clamping head as an independent, firmly interconnected components, it proves to be particularly advantageous to provide a one-piece design. The production and assembly proves to be particularly simple.

The tooth-like projections may be integrally formed, for example, by punching and bending out of the material of the support arms.

In addition, the fastening means may include at least one fastening bolt fixed to the two retaining arms and passing through the intermediate end portion of the contraction hose, for example at least one screw or at least one rivet.

The clamping forces required for the clamping of the end portion can be achieved solely by a corresponding bias of the retaining arms based on their choice of material and / or shape. However, there is also the possibility of additionally or alternatively biasing the two holding arms against one another by means of tensioning means, so that the intermediate end region of the contraction tube is clamped. These tensioning means may be formed by the aforementioned fastening means.

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

In addition to the non-positive existing form-fitting attachment measures, which have penetrating into the contraction tube or the contraction tube passing fasteners, the arrangement is suitably made such that the fastening means engage in the Zugfaseranordnung the contraction tube.

Fig. 1

in einer schematischen Längsschnittdarstellung eine bevorzugte erste Bauform des erfindungsgemäßen Kontraktionsantriebes ohne Darstellung der vorhandenen zahnartigen Vorsprünge,

Fig. 2 bis 4

vergrößerte, perspektivische Darstellungen des in Fig. 1 bei II markierten endseitigen Ausschnittes des Kontraktionsantriebes aus verschiedenen Blickwinkeln, wobei die zahnartigen Vorsprünge wiedenum nicht gezeigt sind, und

Fig. 5 und 6

eine alternative Ausgestaltung des in Fig. 1 markierten Endabschnittes II, wobei die Fig. 5 eine perspektivische Darstellung und die Fig. 6 einen Längsschnitt gemäß Schnittlinie VI-VI aus Fig. 5 zeigt.

The invention will be explained in more detail with reference to the accompanying drawings. In this show:

Fig. 1

in a schematic longitudinal sectional view of a preferred first design of the contraction drive according to the invention without showing the existing tooth-like projections,

Fig. 2 to 4

enlarged, perspective views of the marked in Fig. 1 at II end-side section of the contraction drive from different angles, the tooth-like projections are not shown wiedenum, and

FIGS. 5 and 6

an alternative embodiment of the marked in Fig. 1 end portion II, wherein Fig. 5 is a perspective view and Fig. 6 shows a longitudinal section along section line VI-VI of Fig. 5 shows.

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

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

At its two end regions 5, 6, the contraction tube 2 is closed in a fluid-tight manner. This limits one towards the environment hermetically sealed, elongated Beaufschlagungsraum 7.

At each end portion 5, 6 is a power tabgriffseinheit 8 attached. This is provided with Kraftabgriffsmitteln 12 to which to be moved or to be braced structures or components can be attached directly or indirectly. In the embodiments, the Kraftabgriffsmittel 12 are formed by one or more holes that allow, for example, a Schraubbefestigung or suspension device of the mentioned components.

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

To activate the contraction drive 1, the admission chamber 7 is acted upon by a fluid pressure medium under a predetermined operating pressure. This pressure medium can be fed in via a fluid line 13 communicating with the admission chamber 7. In the exemplary embodiment, the fluid feed takes place 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, in particular in the case of a gas-actuated contraction drive, to generate the drive gas in the interior of the admission space 7 through a pyrotechnic gas generator (not shown).

Upon activation, the loading chamber 7 is subjected to an internal pressure, so that the contraction tube 2 is radially expanded. This radial expansion is accompanied by an axial shortening of the hose length. As a result, the force tapping units 8 are pulled toward each other.

The reason for this behavior is the special structure of the contraction tube 2, in particular in connection with the mentioned tensile fiber arrangement 4 '. In the exemplary embodiment, the tension fiber arrangement 4 has a multiplicity of individual or strands of fibers 4 that are combined to form a crossover configuration. Viewed in the radial direction with respect to the longitudinal axis 15 of the contraction drive 1, the Zugfaseranordnung forms in particular a grid-like structure. During the radial widening of the tube body 3, the grid angles change, so that a tensile force is caused by the contraction tube 2 at the two end regions 5, 6 '. This tensile force, the direction of which is illustrated by arrows 16, is transmitted to the non-positively and preferably positively coupled force tapping units 8, which consequently approach each other in the tensile force direction 16. The activated state achievable in this way is indicated by dash-dotted lines at 17 in FIG.

The contraction tube 2 could also have another, the described performance guaranteeing structure.

Upon actuation, the structures and / or components fixed to the force-tapping units 8 are displaced relative to one another, so that the desired action ensues.

The contraction tube 2 is distinguished by a special embodiment of its two end regions 5, 6 and the force tapping unit 8 fixed thereto. 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, it is also possible to provide deviating designs at the two end regions.

The above as well as the following statements apply equally to all variants shown in the drawing, unless otherwise stated in the individual case.

The contraction tube 2 has at its end region 5 flat shape. This is achieved in particular by virtue of the fact that a contraction tube 2 possessing a hollow cylindrical shape from the outset is compressed at opposite ends by this end region 5, so that diametrically opposite tube wall sections 11a, 11b abut with their inner surfaces flat and tight against each other.

The Kraftabgriffseinheit 8 includes a Kraftabgriffsteil 19, the contraction tube 2 facing front portion forms a fork-like designed clamping head 18. The clamping head 18 has two preferably plate-like designed retaining arms 22, 23 which are adjacent to each other with mutually parallel expansion planes, wherein they define a clamping gap 24 between them.

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

The holding arms 22, 23 each act on their associated hose wall section 11a or 11b, which consequently has a flat shape, wherein the hose wall sections 11a, 11b are pressed together tightly with their mutually facing inner surfaces. The resulting sealing area is indicated at 25 in FIGS. 3 and 6. Thus, the admission area 7 sealed at the end portions 5, 6 of the contraction tube 2 to the environment.

The two retaining arms 22, 23 are expediently formed integrally with each other. They merge into one another in a root region 26, to which a force tapping portion 27, which projects axially away from the contraction hose 2, adjoins, which is equipped with the force tapping means 12. The Kraftabgriffsabschnitt 27 is plate-like flat formed in all embodiments and includes one or more holes passing through it, which form the Kraftabgriffsmittel 12.

In the embodiments of FIGS. 5 and 6, the frictional clamping of the end portion 5 results solely from the mutual bias of the support arms 22, 23, on the basis of their choice of materials and the design of the clamping head 18. Without intermediate end portion 5, the holding arms 22, 23 take one another approximate starting position. For fixing the end region 5, they are briefly spread apart by force application, so that the clamping gap 24 is widened. After the subsequent insertion of the end portion 5, the holding arms 22, 23 are released, firmly squeezing the end portion 5 due to their need to return to the starting position. The clamping head 18 has expediently in this context on 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 clamping means 28 bridging the clamping gap 24. Such a design is in the embodiment of FIGS. 1 to 4 before. As clamping means 28 serve here one or more fastening bolts 32, which are fixed with their respective two ends to the support arms 22, 23 and arranged in the clamping gap 24 Pass through end portion 5 of the contraction tube 2. They are expediently screws or rivets, which are supported with their heads on the side facing away from the clamping gap 24 outside of the respective holding arm 22, 23 and exert in this way the desired clamping force or clamping force on the support arms 22, 23.

A particularly high security against slipping out of the contraction tube 2 from the clamping head 8 is achieved by additional positive fastening measures. Such positive fastening measures result in the embodiment of FIGS. 1 to 4, among others, from the fastening bolts 32 provided there. They penetrate the end section 5, which has been correspondingly perforated beforehand. Since the tensile fiber assembly 4 is penetrated, results in a particularly secure connection.

FIGS. 5 and 6 show the fastening means according to the invention which are fixed to the retaining arms 22, 23 and which engage positively in the clamped end region 5 of the contraction tube 2. They consist of tooth-like projections 33 which protrude from the clamping space 24 facing the inner surface of the respective holding arm 22, 23 in the clamping space 24 inside. As is clearly evident from FIG. 5, they engage in a form-fitting manner into the contraction tube 2. Expediently, the arrangement is such that the tooth-like projections 33 provided on a respective holding arm 22, 23 merely dip into the directly impacted tube wall section 11a, 11b.

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

In the embodiment of Figures 1 to 4 tooth-like projections in addition to the fastening bolts 32 are present, which are not apparent in the drawing, however.

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

Claims (10)

1. Fluid-operated contraction drive with a contraction tube (2), which is subjected to a longitudinal contraction if fluid is admitted to a pressurisation chamber (7) bounded by said tube and which is provided in each of its two end sections (5, 6) with a power take-off unit (8) allowing the take-off of the drive power generated, wherein at least one end section (5, 6) of the contraction tube (2) has a flat shape and is clamped between two retaining arms (22, 23) of a forked clamping head (18) of the associated power take-off unit (8), wherein the opposite tube wall sections (11a, 11b) are tightly pressed together with their inner surfaces, and wherein fastening means (32, 33) are provided, which are secured to the retaining arms (22, 23) and positively engage the clamped end section (5, 6) of the contraction tube (2), characterised in that the fastening means are at least partially represented by tooth-like projections (33) of the retaining arms (22, 23).
2. Contraction drive according to claim 1, characterised in that the contraction tube (2) is a body with a hollow cylindrical contour, the flat shape of its at least one end section (5, 6) being based on clamping in the forked clamping head (18).
3. Contraction drive according to claim 1 or 2, characterised in that the two retaining arms (22, 23) of the clamping head (18) are designed in one piece.
4. Contraction drive according to any of claims 1 to 3, characterised in that the two retaining arms (22, 23) have a plate-like shape.
5. Contraction drive according to any of claims 1 to 4, characterised in that the tooth-like projections (33) are punched and bent from the material of the retaining arms (22, 23).
6. Contraction drive according to any of claims 1 to 5, characterised in that the fastening means additionally comprise at least one mounting bolt (32) secured to the two retaining arms (22, 23) and passing through the end section (5, 6) of the contraction tube (2), which is located in between.
7. Contraction drive according to claim 6, characterised in that at least one mounting bolt (32) is represented by a screw or rivet.
8. Contraction drive according to any of claims 1 to 7, characterised in that the two retaining arms (22, 23) bound a clamping space (24) which the contraction tube (2) engages with its flat-shaped end section (5, 6), the two retaining arms (22, 23) being preloaded from opposite sides towards the end section (5) of the contraction tube (2) by clamping means (28) bridging the clamping space (24).
9. Contraction drive according to any of claims 1 to 8, characterised in that the contraction tube (2) comprises a tubular body (3) made of a rubber-elastic material and a tension fibre arrangement (4) coaxial with the tubular body (3) and expediently embedded in the wall of the tubular body (3.
10. Contraction drive according to claim 9, characterised in that the tension fibre arrangement (4) comprises tension fibres arranged in a cross-over configuration.

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