EP0778923A1

EP0778923A1 - Fluid actuator

Info

Publication number: EP0778923A1
Application number: EP96910891A
Authority: EP
Inventors: Branislav Previsic
Original assignee: ATI ALTERNATIVE TECHNISCHE INNOVATION AG
Current assignee: ATI ALTERNATIVE TECHNISCHE INNOVATION AG
Priority date: 1995-05-09
Filing date: 1996-05-07
Publication date: 1997-06-18
Also published as: JPH10502990A; WO1996035877A1

Abstract

The actuator of the invention consists of a plurality of supports (4) consisting in turn of a plate (2) and a shaft (3). Said plurality of supports (4) is fitted on a frame (1) and arranged to form a stack. In the axial direction of said stack there extend, for example, three pump units (5) which are anchored on the one hand on the frame (1) and on the other on the topmost plate (2) and are also covered there. In addition, the topmost plate (2) bears a component (9) which may be, for instance, be a tool, a measuring device or the like. At the point where a plate (2) lies on the shaft (3) of the support below it there is an elastomer pad (12) permitting a relative angular movement between two neighbouring supports (4). Three fluid lines (7) open into the frame (1). If pressure is applied to a pump unit (5) via the corresponding line (7), said unit bulges between the plates (2) and shortens. The result of this is that the actuator bends towards the side of the pressurised pump unit (5). The pressure supply to each individual pump unit can be independently controlled, each of point of a spheroidal rotation surface being reachable by the component (9).

Description

Fluidic actuator

The present invention relates to a. Betäti¬ fluidic constriction means according to the preamble of claim 1, WEL ches can be controlled on a ball-like surface of revolution substantially at every point ^'.

Fluidic - hydraulic or pneumatic - actuators or actuators are known in many designs. They are mostly based on translational and / or rotary movements or combinations of such: hydraulic cylinders and hydraulic motors are the prototypes of these. More complex actuators are often composed of these prototypes mentioned. Certain tasks, however, are either unsolvable with such compositions or then very expensive.

From US 5,085,283 and US 5,148,877 devices are known which are designed in an articulated manner and make it possible to transmit torques with respect to the current and local axis of rotation. These devices - from the two documents mentioned - can be curved by external forces, that is to say passively, and can be rotated about their own curved axis. The object which is to be achieved with the present invention consists in creating a fluidic actuating member which consists of a multiplicity of essentially identical, axially strung together bodies and which is brought into a predetermined overall curvature by the targeted use of fluidic pressures can be.

The solution to the stated problem is reproduced in the characterizing part of patent claim 1 with regard to its main features, and in those of patent claims 2 to 22 with regard to further advantageous developments. The concept of the invention is explained in more detail in several exemplary embodiments with the aid of the attached drawing. Show it

1 shows a first exemplary embodiment of an actuator,

2 shows a first embodiment with a plate, 3 shows a detail of FIG. 1 in the actuated position,

4 shows a schematic illustration of an actuating member with the surface coated thereby,

5 shows a first embodiment of a single support element,

6 shows a second exemplary embodiment of an individual supporting element,

7 shows a third embodiment of an individual support element,

8 two supporting elements according to FIG. 6 in cooperation,

9 shows a second embodiment of a plate,

10 two supporting elements interacting with a third exemplary embodiment of a plate,

11 two supporting elements interacting with a uniaxial joint,

12 two supporting elements with universal joint interact,

Fig. 13 two support elements with an elastic joint in

Cooperation,

Fig. 14 two support elements with an elastic universal joint in

Cooperation,

15 several supporting elements with a flexible shaft in cooperation,

16 several supporting elements with a pump organ and a coil spring, 17 two supporting elements with a longitudinally elastic shaft in cooperation,

18 shows an exemplary embodiment with an external element taking over the supporting function,

19 shows an embodiment with asymmetrical Blattfe¬,

Fig. 20 shows an embodiment with a symmetrical leaf spring.

In Fig. 1 a first embodiment is a ^'inventions to the invention the actuating member shown. A round plate 2, for example, is fastened on a frame 1. This plate 2 carries a shaft 3, likewise hollow in the sense of an example, which is connected to the plate 2. This connection can either be made by welding or by the fact that plate 2 and shaft 3 are produced in one piece by turning, pressing, forging or casting. On the shaft 3 of the plate 2 mentioned there is another plate 2, identical to the first, which in turn carries a shaft 3. In this way, a column or a stack of support elements 4 is formed, each such support element 4 consisting of a plate 2 and a shaft 3. The type of mounting of a plate 2 on the underlying shaft 3 is explained in more detail in FIGS. 5, 6, 7. Three pump elements 5, for example, each anchored to the top and bottom plate 2, extend over the entire height of the column consisting of support elements 4.

These pumping elements 5 are known, for example from CH patent application 01 298 / 94-3. A pumping element 5 essentially consists of an inner elastomeric tube, which is surrounded by a longitudinal reinforcement made of less elastic fibers. For the purpose of stabilizing the fibers, the entire reinforcement is embedded in a matrix made of a further elastomer. If such a pump organ 5 is filled with a fluid and pressurized, it will bulge on the one hand, but shorten on the other. In the complete invention, the plates 2 - as can be seen from FIG. 2 - have three holes 6, each offset by 120 °. The pump organ 5 is pulled through this. If the fluid contained therein is now pressurized, a belly always arises in the pump organ between two adjacent plates 2; at the same time, the distance between two plates 2 is reduced: the upper support element 4 is crooked with respect to the lower. This situation is shown in Fig. 3. If the carrying elements 4 are identical, the inclination of each individual to the underlying column results in a circular arc for the entire column. Furthermore, three lines 7 are shown in FIG. 1, which lead to fluid pumps or pressure accumulators (not shown). By suitably controlling the fluid pressures in the three pumping organs 5, it is possible to coat a rotationally symmetrical surface 8 with the upper end of the column, as is shown in FIG. 4. This area is of course dependent on the height of each support element 4, the maximum inclination angle between two support elements 4 and the number of such support elements 4 mentioned.

In Fig. 1 the uppermost supporting element 4 carries an organ 9. This organ 9 can be a tool, a measuring instrument or any other device which can be moved in the manner described on the surface 8 mentioned or can and should be positioned on it .

5, 6, 7 show variants of support elements 4 which differ with regard to the shape of the connecting surface on shaft 3 and plate 2 (of the upper support element 4). Each shaft 3 carries an upper contact surface 10, each plate 2 a lower contact surface 11. In FIG. 5 the two contact surfaces 10, 11 are spherical sections of identical radius of curvature. In this configuration of the contact surfaces 10, 11, it is provided that they slide on one another, for which purpose the contact surfaces 10, 11 can be equipped with low friction. 6, the contact surfaces 10, 11 are conical, the upper contact surface 10 having a narrower cone than the lower contact surface 11; overall, however, both cones are very wide with an opening angle of more than 120 °. With regard to the relation of the opening angles of the cones, the statements made with regard to FIG. 6 also apply to FIG. 7, only here the opening angle is considerably smaller, for example <90 °. While, as described, spherical contact surfaces 10, 11 slide on one another, conical contact surfaces 10, 11 provide for inserting a cushion 12 made of an elastomer between the contact surfaces 10, 11, which pad is glued to the two contact surfaces 10, 11. The relative mobility of two support elements 4 is then determined both by the steepness of the conical contact surfaces 10, 11 and by the thickness and the Shore hardness of the elastomeric cushion 12.

The use of the elastomeric cushion 12 mentioned has the advantage on the one hand that there is no dry friction between two support elements 4, and on the other hand it causes a restoring force which is present in the three pumping glands 5 when the fluid pressure is completely eliminated. the actuator is straight.

FIG. 9 shows a further exemplary embodiment of a carrying element 4. While the shaft 3 is unchanged here from the representations of FIGS. 1 to 3 and 5 to 8, the plate 2 is essentially hexagonal. The holes 6 are not drilled in the plate 6, for example, but consist on the one hand of a semicircular recess in the plate 2, and on the other hand from the inner shape of a likewise substantially semicircular bracket 13, which is fastened to the plate 2 with screws 14, for example.

2, 5 to 9, the shaft 3 has a bore 15. On the one hand it serves to reduce the weight, on the other hand it enables measurement and control lines for the organ 9 to be carried out through the entire actuating element. For certain applications it may be sufficient if the organ 9 can only reach points in one plane. 10 shows such an embodiment. Instead of three pump elements 5, there are therefore only two, the axes of which are connected to the Axis of the shaft 3 lie in the same plane. The support elements 4 can - with the changes mentioned - be made essentially the same or corresponding. Since the pivoting of the support elements 4 is only provided within one plane in this exemplary embodiment, the contact surfaces 10, 11 can also be modified accordingly. Instead of a spherical surface - in accordance with FIG. 5, a cylindrical surface then occurs. 11 to 14 show further exemplary embodiments of support elements 4, which are inventive on the one hand for uniaxial (ie lying in one plane) and on the other hand for biaxial movements of the actuating member.

In the exemplary embodiment of the support element 4 according to FIG. 11, the shaft 3 is divided into an upper part 16 and a lower part 17. Apart from two projections 18 (in FIG. 11), only one is visible, the other is covered) ¬ part 16 just cut below. The protrusions 18 are in the form of half cylinders. The lower part 17 is shaped so that it forms two bearing pans 19 for the projections 18; to the side of the bearing pans 19, the lower part drops, for example, by an angle α. The maximum pivoting of two adjacent support elements 4 is thus defined. The two pumping organs 5 are then arranged analogously to FIG. 10. In the exemplary embodiment according to FIG. 12, the shaft 3 is divided into three parts; an upper part 16, a lower part 17 and a middle part 20. Upper part 16 and lower part 17 are designed as described in FIG. 11. The middle part 20 is shaped and designed on its top, like the bottom part 17, on its bottom, like the top part 16. The axis of the cylindrical projections 18 of the top part 16 is perpendicular to that of the center part 20, so that the plate 2 of the in Fig. 12 upper support member 4 can perform a two-axis pivoting movement with respect to that of the lower support member 4; a universal joint is created. Corresponding to the biaxial nature of this exemplary embodiment shown in FIG. 12, it may be sensible and desirable to use four pump elements 5 (not shown in FIG. 12), two for each pivot axis. Since the two or four pump organs 5 in Operation all under a certain minimum pressure, tensile forces always act between two support elements. The drawn joints cannot therefore fall apart.

Instead of the drawn joints - consisting of cylindrical projection 18 and bearing socket 19 - other rotary joints can be used without departing from the inventive concept.

The exemplary embodiment according to FIG. 13 has a uniaxial elastic joint. In the embodiment shown, the shaft 3 is made relatively thin-walled and has two deep incisions 21. The remaining wall is rotated by 90 ° and thus forms two springs 22. According to the uniaxiality, only two pumping organs 5 are again provided. Instead of the elastic joint shown, a different one can be used that performs the same function.

In the exemplary embodiment according to FIG. 14 there are two elastic joints, which are designed analogously to that of FIG. 13, separated by a central part 23. This creates an elastic universal joint. This embodiment can again be equipped with four pump elements 5, in accordance with the biaxial nature. Here too, differently shaped elastic joints can take the place of the ones shown. . Of course, the embodiments according to Figures 11 and 13 are moved also in the three pumping ^organs' 5 in the same manner can; the control of the fluid flows is to be done differently. In reverse of what has just been said, the exemplary embodiments according to FIGS. 1, 3 and 5 to 8 can also be moved by four pump elements 5. The plates 2 shown in FIGS. 2 and 9 are then to be equipped with four holes 6 instead of three.

FIG. 15 shows an exemplary embodiment in which the individualized elastic joints from FIGS. 13 and 14 are replaced by an elastic rod 24. This extends through the entire length of the actuating member and is attached to the plates 2, for example by one Ring 25 supported. The rod 24 can also be designed as a tube. As materials ara id or carbon fiber reinforced plastics are known for such elastic tubes or rods 24.

Another exemplary embodiment is shown in FIG. 16:

The plates 2 are equipped with only one pump organ 5. The restoring forces are from a coil spring

26 applied, which can be adjusted so that the actuating member according to FIG. 16 has the full swivel range made possible by the uniaxial joint. Since the device of this type always exerts compressive forces on the joints, joints according to FIG. 11 are also used here. The helical spring 26 can be a continuous one, which is fixed to each plate 2; a second solution according to the invention is to fasten individual coil springs 26 between two plates 2 each. The exemplary embodiment according to FIG. 17 has an additional - axial - degree of freedom compared to the previously shown. Instead of the axially rigid element (shaft 3 with variations) here is a preferably hard coil spring

27 used. Between two plates 2 there are preferably four pumping elements 5, each of which extends over the whole

Extend length of the actuator. Depending on the selected pressure conditions, the actuating element designed in this way can only be pivoted, only shortened, or controlled in combination of both types of movement. The shape of the plates 2 is not essential to the invention. Instead of circular plates 2, other shapes can also be used, as described with reference to FIG. 9. Polygonal shapes, radially extending rods, which attach to the support elements 4, are also within the meaning of the invention, as are other configurations which produce a rigid connection from the support element 4 to the point of attack of the pump elements 5. The term "plate 2" is to be understood in this expanded sense throughout, as for a component which extends essentially radially with respect to the local axis direction of the actuating member. The term “shaft 3” is used for the component that extends in the local axial direction. A plate 2 and a shaft connected to it thus form together men a support element 4. The different design of these support elements 4 is according to the invention.

FIG. 18 shows an embodiment analogous to that of FIG. 11, but with reversal of the force flows: the two pump elements are not arranged on the outside of a shaft 3, but rather on the inside of an essentially tubular support body 31. Two adjacent ones in each case Supporting bodies 31 are connected to one another in an articulated manner, as already shown in FIG. 11, namely in such a way that a cylindrical projection 18 engages in a likewise cylindrical bearing socket 19 at two opposite points on the circumference of the supporting body 31. The pumping elements 5 are also anchored to two plates 2, which in turn are attached essentially at half the height of the supporting body 31. Instead of the joint formed from the elements 18 and 18 there are also elastic joints in the sense of the invention, in complete analogy to those shown in FIG. 13. Likewise, the support bodies 31 can be equipped with two pairs of joints offset by 90 ° each, as shown in FIGS. 12 and 14.

19 is a representation of a variant of the representations of FIGS. 16 and 17. The position of a support element is taken here by a leaf spring 32, which extends from plate 2 to plate 2, or, as a long leaf spring trained, each attached to the plates 2. Each plate 2 has a hole 6 for receiving a pump goose 5. If the pump organs are pressurized, they shorten - as in all the exemplary embodiments - and the device bends to the right in the illustration according to FIG. 19. However, one possibility according to the invention is also to use the leaf spring 32 bent to the left, so that an angular range can be covered on both sides of the extended position of the leaf spring 32. In FIG. 19, optional tubular elements 33 are also entered, which, however, do not perform a static but only a protective function. FIG. 20 shows a variant of the exemplary embodiment from FIG. 15. Instead of an elastic rod 24, a leaf spring 32 is also used here, as in the previous one Embodiment is attached to each plate 2. Two pump organs 5 act as antagonists, one on each side of the leaf spring 32. This allows it to be bent on each side. The tubular elements 33 in turn only have a protective function.

Common to all Asführungsbeispiele is the presence of elements that take on the supporting function (shafts 3, rods 24, supporting body 31, leaf springs 32) and are each attached on both sides to a perpendicularly extending plate 2, of elements that take on the pulling function (pumping elements 5) and can exert tensile forces on the plates, from elements which apply restoring forces (pump elements 5, elastomeric cushions 12, springs 22, coil spring 26) and from articulated elements (contact surfaces 10, 11 with the elastomeric cushions 12, projection 18 and bearing socket 19 , Spring 22, shaft 24, leaf spring 32).

Claims

claims

1. Fluidic actuator, which can be controlled by changing fluid pressures essentially at any point on at least one circle-like surface of revolution, characterized in that

- It consists of a large number of supporting elements (4), which in turn are divided into a plate (2) and elements (essentially perpendicular to the plates (2) that extend and each connect two adjacent plates (2)) 3, 24, 31, 32), which can take over the supporting function,

a supporting element (4) is placed axially on the next, in such a way that a stack of supporting elements is created,

- Each plate (2) has at least one hole (6), the holes (6) of all plates (2) are arranged coaxially and accommodate a pumping element (5), the pumping element consisting of at least one elastomeric hose reinforced with little stretchable fibers which is closed at one end and can be fed at the other by a line (7) with a fluid under controllable pressure,

the support elements (4) have means by which two adjacent support elements can be inclined at an angle to one another and this inclination can take place in at least one predetermined plane,

- The first support element (4) of the stack is fastened to a frame (1) and the last support element

(4) of the stack carries an organ (9),

- The at least one pump organ between the plates

(2) Belly forms and therefore shortens when it is pressurized. - The stack deforms like a circular arc when the pump goose (5) is shortened.

2. Fluidic actuator according to claim 1, characterized in that the length of the supporting function elements (3, 24, 31, 32) is essentially unchangeable.

3. Fluidic actuator according to claim 1, characterized in that the two adjacent plates (2) connecting and taking over elements take over each consist of a shaft (3) which is arranged in the central axis of the plate (2).

4. Fluidic actuator according to claim 3, characterized in that two adjacent support elements (4) have contact surfaces (10, 11) both on the plate (2) and on the shaft (3) and that the mutual inclination of two adjacent ones Carrying elements (4) causes a relative movement of the said contact surfaces.

5. Fluidic actuator according to claim 4, characterized in that the contact surfaces (10, 11)

Ball sections are of the same radius of curvature.

6. Fluidic actuator according to claim 4, characterized in that the contact surfaces (10, 11) are of different steepness and are separated by a cushion (12) made of an elastomer.

7. Fluidic actuator according to claim 4, characterized in that the contact surfaces (10, 11) are cylindrical sections of the same radius of curvature.

8. A fluidic actuator according to claim 1, characterized in that the two adjacent plates (2) connecting and taking over the supporting function elements each consist of a tubular Tragkör¬ per (31) and the plate (2) essentially in its interior half height is attached.

9. Fluidic actuator according to claims 2 and 8, characterized in that the means for tilting two adjacent support elements (4) against each other consist of joints, each of which is contained in the support function element (3, 31).

10. Fluidic actuator according to claim 9, characterized in that the joints are single-axis hinge joints, the axes of which perpendicularly penetrate the longitudinal axis of the shaft.

11. Fluidic actuator "according to claim 10, characterized in that each support element has a single joint.

12. Fluidic actuator according to claim 10, characterized in that the axes of all joints run parallel.

13. Fluidic actuator according to claim 10, characterized in that the axes of the joints of two adjacent, supporting functions, elements (3, 31) are perpendicular to each other.

14. Fluidic actuator according to claim 10, characterized in that each support element (4) has two uniaxial hinge joints, the axes of which are perpendicular to one another.

15. Fluidic actuator according to claim 9, characterized in that the joints are elastic Biege¬ joints.

16. Fluidic actuator according to claim 15, characterized in that each support element (4) has a unique joint.

17. Fluidic actuator according to claim 15, characterized in that the axes of all joints run parallel.

18. Fluidic actuator according to claim 15, characterized in that the axes of the joints of two adjacent support elements (4) are perpendicular to each other.

19. Fluidic actuator according to claim 15, characterized in that each support element has two elastic bending joints, the axes of which are perpendicular to one another.

20. Fluidic actuator according to claim 9, characterized in that the whole, supporting function assuming element (24, 32) is designed to be flexible.

21. Fluidic actuating element according to claim 20, characterized in that the flexurally elastic element which takes over the supporting function is an essentially cylindrical shaft (24).

22. A fluidic actuator according to claim 20, characterized in that the flexible, load-bearing function, element is a leaf spring (32).

23. Fluidic actuator according to claims 1 and 20, characterized in that the shaft (3) is both flexible and longitudinally elastic.

24. Fluidic actuator according to claim 1, characterized in that

- Each plate (2) has two holes (6), which are arranged symmetrically with respect to the longitudinal axis of the support element (4). - Both sets of said holes (6) are coaxially arranged in the plurality of plates (2),

- The fluidic actuating element has two pump elements (5) arranged parallel to one another, which can be pressurized independently of one another.

25. Fluidic actuator according to claim 1, characterized in that - each plate (2) has three holes (6) which are arranged symmetrically with respect to the longitudinal axis of the support element (4),

- Both groups of said holes (6) in the plurality of plates (2) are each arranged coaxially, - The fluidic actuating element has three pump elements (5) arranged parallel to one another, which can be pressurized independently of one another ¬ nen.

26. Fluidic actuator according to claim 1, characterized in that

each plate (2) has more than three holes (6), which are arranged symmetrically with respect to the longitudinal axis of the support element (4), - the sheets of said holes (6) in the plurality of plates (2) are each arranged coaxially,

- The fluidic actuating element has a plurality of pump elements (5), which correspond to the number of holes (6) in each plate and are arranged parallel to one another and can be pressurized independently of one another.