US3605780A

US3605780A - Electromechanical fluidic transducer

Info

Publication number: US3605780A
Authority: US
Inventors: Walter Kranz
Original assignee: Messerschmitt Bolkow Blohm AG
Current assignee: Airbus Defence and Space GmbH
Priority date: 1968-09-21
Filing date: 1969-09-17
Publication date: 1971-09-20
Anticipated expiration: 1988-09-20
Also published as: GB1235980A; FR2018598A1; DE1774859B1

Abstract

AN ELECTROMECHANICAL FLUIDIC TRANSDUCER HAS A FLOW FEED LINE COMMUNICATING WITH TWO FLOW OUPUTS. TWO CONTROL SIGNAL RESPONSIVE ELECTROMAGNETIC DEVICES ARE OPERABLE TO SELECT THE FLOW OUPUT, EACH CONTROLLING FLOW RELATIVE TO A RESPECTIE OUTPUT. A SIGNAL FLOW SWITCHING ELEMENT IS MOVABLE, UNDER THE INFLUENCE OF FLUID FLOW, INTO FLOW BLOCKING RELATION IN A SELECTED ONE OF THE FLOW OUTPUTS, AND THE SWITCHING ELEMENT IS LOCKABLE IN ITS BLOCKING POSITION BY THE ASSOCIATED ELECTROMAGNETIC DEVICE. THE FLOW SWITCHING ELEMENT IS A FORKED ELEMENT, AND EITHER MAY BE PIVOTED AT THE FORK BETWEEN THE TWO OUTPUTS OR MAY BE FLEXIBLE, IN THE FORM OF A LEAF SPRING. ADJUSTMENT CANALS OR DUCTS COMMUNICATE WITH THE FLOW FEED OR SUPPLY LINE FROM OPPOSITE SIDES TO COMPENSATE FOR ASYMMETRY OF THE FLOW CONTROL ELEMENT.

Description

p 1971 W. KRANZ suscwnouncmmrcu m.u1mc umusnucmn Filed Sept. 17, 1969 mvemoa Walter Kranz Y7);%JM'77TW AT'|ORNEYS United States Patent O 3,605,780 ELECTROMECHANICAL FLUIDIC TRANSDUCER Walter Kranz, Munich, Germany, assignor to Messerschmitt-Bolkow-Blohm Gesellschaft mit beshrankter Haftung, Ottobrunn, near Munich, Germany Filed Sept. 17, 1969, Ser. N0. 858,656 Claims priority, application Germany, Sept. 21, 1968, P 17 74 859.3 Int. Cl. Fl5c 3/08 U.S. C]. 137-815 8 Claims ABSTRACT OF THE DISCLOSURE An electromechanical fluidic transducer has a flow feed line communicating with two flow outputs. Two control signal responsive electrornagnetic devices are operable to select the flow output, each controlling =flow relative to a respective output. A single flow switching element is movable, under the influence of fluid flow, into flow blocking relation in a selected one of the flow outputs, and the switching element is lockable in its blocking position by the associated electromagnetic device. The flow switching element is a forked element, and either may be pivoted at the fork between the two outputs 01 rnay be flexible, in the forn1 of a leaf spring. Adjustment canals or ducts communicate with the flow feed or supply line from op posite sides to compensate for asymmetry of the flow control element.

BACKGROUND OF THE PRIOR ART A known electromechanical fluidic transducer has two control vanes provided in place of the control -jets of the conventional jet type fluidic transdncers. These control vanes are mounted pivotally or rotatably below the inlet port of the supply jet and, in their rest position, they rest against the Walls of the flow cham'ber. In this arrangement, the fluid or gas flow clings to one wall of the flow chamher, due to the Coanda effect. In order to redirect this flow, the control vane on the flow side can be turned into the flow in a pulse fashion by means of an externally mounted electrornagnet.

This known transducer has the drawback that the flow is switched to the other output if the output in use is blocked, or responsive to a temporary backup in the output in use. Due to the mentioned Coanda effect, the flow continues in the new direction even if the previously used output again is free. Furthenmore, it is cornpletely uncertain, after an arbitrarily short interruption of the input flow, as to which wall of the flow charnber the flow will cling that is, through which output the flow Will proceed.

In another known electromechanical fluidic transducer, a fluid flow of a wall jet element is switched by control currents through laterally arranged control jets. The main flow, after being switched, forces a wedge-shaped 0bstruction away from that wall along which the flow happens to go. The obstacle 0r obstruction is provided with electrical contacts and closes a circuit if a respective one 0f the two side Walls of the output opening is touched by the obstruction.

Thereby, fluid signals can be converted into electrical signals with the aid of this transducer, but electrical signals cannot 'be converted into fluid-mechanical signals. This transducer is not suited for inverse operation, as, for switching in the direction of the flow, by electromagnetic movement of the wedgeshaped obstruction, energies cf the order of the dynamic energy of the flowing medium are required. In such inverted operation of this transducer, the control jets furthermore would lose their function.

3,605,780 Patented Sept. 20, 1971 "ice SUMMARY OF THE INVENTION This invention relates t0 electromechanical fluidic transducers and, more particularly, to a novel and improved electromechanical fluidic transducer having a flow feed or supply line and two flow outputs, and in which two electromagnetic devices are operable to select the flow output responsive to electrical signals.

T he objective of the invention is to provide an electromechanical fluidic transducer which, in an economical manner, converts weak electrical signals into strong fluidrnechanical signals, and the flow direction of which is changed neither by a brief interruption of the input flow nor by a brief backup in the output then in use, nor by complete blocking of the flow output then in use.

In accordance With the invention, an electromechanical fluidic transducer of the general type mentioned above is provided in which there is associated, with the electromagnetic devices, a signal switching element which, under the influence of the flow, can be moved into one or the other of the flow outputs, and can be locked in this position by the associated electromagnetic device.

In accordance with the preferred form of the invention, the switching element, arranged between the flow outputs of the transducer, is a fork which can rotate about a pivot in such a manner that its blade-shaped ends extend, opposite to the direction of fluid flow, into the two flow outputs. For maximurn lateral deflection, one Madeshaped fork end always rests against the onter wall of one flow output, completely closing this flow output, while the other blade-shaped fork end rests against the inner wall of the other flow output. Externally of the flow outputs, and near the free ends of the fork, the electromagnets are arranged and are operable to lock the fork.

The electromagnets operate with holding current, and are so connected that only one electrornagnet is energized at any one time. In the operating condition of the transducer, the then energized electromagnet need exert only a weak force to lock the fork end which is adjacent thereto. If the then energized electromagnet is de-energized, by an electric input signal, and the other electromagnet is energized, the fork is rotated to the opposite side and locked in that position by the other electro magnet.

The main energy for switching of the fork is taken from the fluid flow. In addition, the field, just building up, cf the magnet then energized acts in an accelerating sense on the fork during rotation of the latter. From this there results the advantage that the rotation of the fork sets in immediately after the switching of the electromagnets, and not only when the field of the electrornagnet then energized is fully built up. If both electromagnets are deenergized, the fork oscillates by itself.

In another enrbodiment of the invention, the fork is pivotally mounted at the ve1tex of the two flow outputs.

The invention also provides for resiliently mounting, in place of the fork, a leaf spring notched a1; its free end in the shape of a fork, this leaf spring being positioned at the vertex of the flow outputs. Such a leaf spring can be mounted more simply than a rigid, pivotal fork.

In accordance with a further embodiment of the invention, adjustrnent canals or ducts are arranged upstream from the free ends of the fork or of the leaf spring, and extend to the flow supply line frorn two opposite sides. These adjustrnent canals serve to compensate for asymmetry of the fork or of the leaf spring, or of their mountings. The adjustment canals furthenrnore make possible to make the switching time to one preferred direction smaller than that to the other direction.

An object of the invention is to provide an improved electrornechanical fluidic transducer.

Another object of the inventi-on is to provide such a tramsducer which, in an ecomomical manner, converts Weak electrical sigmals to streng fluid-mechanical signals.

A further object of the invention is to provide such a transdncer in which the flow direction is mot chamged either by a brief imterruption f the input flow, a brief backup in the ontput then in use, or complete biocking of the flow output then in nse.

Another object of the imvemtion is to provide such an electrornechanical fluidic transducer im which a single switching element is electromagnetically locked in an adjusted position after having been moved to the adjusted position respomsive to fluid flow.

A further object of the invention is to provide such an electromechanical fluidic tramsducer requiring only a very small energy for electromagnetic locking or holding means.

For an umderstanding of the principles of the imvemtion, referemce is made to the following descn'ption of typical embodiments thereof as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a sectional view of an electrornechamical fluidic transducer, embodying the imvention, and having a fork mounted between the flow ontputs;

FIG. 2 is a view, similar to FIG. l, of an electromechanical fluidic transducer havimg a fork moumted at the vertex of the flow outputs;

FIG. 3 is a sectional view of amother embodiment of electromechanical fluidic transducer, in accordance with the invemtion, and having a leaf spring mounted at the vertex 0f the flow outputs; and

FIG. 4 illustrates a further embodimemt o-f the imventiom including adjustment camals in the flow supply line.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. l, an electromechanical fluidic transducer I imcludes a non-metallic housimg 1 in which are machined or otherwise forrnecl a fluid flow supply line 2 and two symmetrical flow outputs 3 and 4. Flow outputs 3 and 4 are separated by a part of homsing 1 which forms a divider having a point or vertex in the direction toward flow supply line 2, the vertex heilig indicated at 21. Below or downstrearn of vertex 21, parts 27 and 28 of the immer Walls cf the respective flow outputs 3 and 4 are displaced, With respect to each other, so that

shoulders

19 and 20, respectively, are provided.

A switchimg element, in the form of a symmetrical fork 5 having blade-shaped emds 6 and 7, is mounted between flow outputs 3 and 4 for pivoting about a pivot 8-. Fork 5 is so balamced Ihat its cemter of gravity lies at its pivot or fulcrum. The fork may cormprise a ferromagnetic metal, or a material containing ferromagnetic metal.

At maximum deflection of fork 5, for exarnple to the right, blade-shaped fork end 6 closes flow ontput 3 completely. In this position, the other fork and 7 rests against the immer wall 28 of flow output 4, below shoulder 20, so that output 4 is completely open.

In the proximity 0-f the limits of movement of fork ends 6 and 7, respective electromagnets 9 and 10 are arranged im the outer Walls of flow outputs 3 and 4, and outside of these flow outputs. Electromagnets 9 and 10, which are shown omly schematically in the drawing, each comprises an exciter windimg 14 and 15, respectively, and havimg respective

electrical Ieads

11, 12 and 16, 17, and respective

electromagnetic cores

13 and 18. Electrormagnets 9 and 10 are so conmected that they operate With holdimg current only, and also so that only one electromagnet 9 or 10 is emergizecl at any one tirne.

With electrornagnets 9 and 10 de-energized, the arrangement operates in the following manmer. lf a liquid or gas flow is fed through flow supply line 2 and fork 5 is rotated to the right, as in FIG. l, a part of this flow jams up at the entramce to flow output 3. The flow then goes through flow output 4. Vortices form, im this process, a1 the shoulder 20 under which rests the left blade-shaped fork and 7 at the immer Wall 28 of flow output 4. These vortices ull the fork end 7 imt-o the flow outpuc 4-. As soom as the left fork end 7 is seized by the flow, it is pressed agaimst the outer wall of flow output 4. AI the same time, right fork emd 6 is rotated away frorn the unter wall of flow output 3 and imto engagernent with the immer Wall 27 of this flow output.

In this position of fork 5, flow jams up im front of flow output 4. 1f the outpu*t 4 is filled With the flow medium co about the height of vertex 21, the flow flips over to the flow output 3. Now vortices are forrned in the flow output 3 at the shoulder 19. These pull the right-hand fork end 6 into the flow output 3. As soom as this fork end 6 is seized by the flow in output 3, it is pushed to the outer wall of outpnt 3. At the sarne time, the 1ef t-hand fork emd 7 of fork 5 is rotated away from the outer Wall cf flow Output 4 to the immer wall 28 thereof. Now the flow jams up again in flow output 3 until it again flips over imto the output 4.

In the volume defined by the respective fork emds 6 and 7, the

respective shoulders

19 and 20, and the respective adjoiming parts of the immer Walls 27 or 28, and the surrounding space, rapid pressure equalization is possible, and this prevents damping of oscillatiom of -the fork. For this pressure equalization, there can be used the spaces between fork 5 and the inner walls 27 and 28, as may be seen frorn FIG. 1, 0r special equalization apertures may be provided.

Through the action of electrornagnets 9 and 10, the described arramgement becornes a bistable electromechanical fluidic trandsucer. The electromagnet 9 or 10, respectively, emergized at any one tirme, has, in the operatimg comdition of the electromechanical fluidic tramsducer, only to lock the fork end 6 or 7, respectively, which is adjacent 10 it, agaimst the outer wall of the respective flow output chanmel 3 or 4.

If, for exarnple, the energized electromagmet 9 is deenergized by means of an electric imput sigmal and the other electrornagnet 10 is energized, right-hamd fork end 6 is no lomger locked by electrornagmet 9 and fork 5 is rotated to the left up against the unter Wall of flow output 4. In this position, left-hamd fork end 7 is locked by the emergized electromagmet 10.

The main energy for pivoting of fork 5 is supplied, as described above, by the flow. Additionally the field, for example of the electromagnet 10, Which is just bnilding up, acts on left-hamd fork end 7 in an accelerating manner during pivotimg of fork 5.

A secomd embodimemt of an electromechanical transducer is illustrated in FIG. 2, and is desigmated With II. It difiers from tramsducer I, of FIG. l, in that fork 5 is mounted at the vertex 21 of the two flow outputs 3 and 4. Electrornagnets 9 and 10 are arranged, as in FIG. l, outside the flow passages at the height of the rast positions 0f fork ends 6 and 7. Through the arrangernent cf the fork at vertex 21, the jammed-up length betweem fork end 6 or 7, respectively, and flow feed line 2 is shortened. Thereby, an increase of the frequency of oscillation, and thus 0f the switching frequency of the transducer, is made possible.

FIG. 3 illustrates am electromechanical fluidic transducer III in which a leaf spring 22, notched at its upper end to the shape of a fork, is rigidly clamped at vertex 21 of flow outputs 3 and 4 t0 serve as a switching elememt. This embodiment cf the invention makes possible a simple mountimg of the oscillating switching element. The spring force of the 1eaf spring switchimg element is, at the same tirne, utilized for switching of the switching element.

If, as illustrated in FIG. 3, the flowing medium flows through flow output 4, the Coanda eflect occurs below the. shoulder 26, that is, below shoulder 26, the flow clings t0 the outer Wall of flow output 4. The flow will stay at this Wall if electromagnets 9 and 10 are switched and leaf spring 22 is bent toward the left and specifically until the left-hand fork end 7 rests against the outer Wall f flow output 4. The embodirnent of the flow feed line 2 illustrated in FIG. 3 therefore produces an additional protection against leaf spring 22 swinging back due to its own restoring force, and against the influence of the flow, before reaching the maximum lateral deflection. This form of the flow feed line can, of course, also be applied to the embodiments of the invention shown in FIGS. 1 and 2.

The embodiment of the invention shown at IV in FIG. 4 difiers from the transducer II, described above, only in that adjustment canals 23 and 24 are arranged upstrearn of fork 5, to the right and left, respectively, of flow feed line 2. These adjustrnent canals serve to cornpensate for asymmetries of fork or its mounting. Furthermore, they merke possible a decrease in the switching time to one preferred direction as compared to the opposite direction. The adjnstrnent canals 23 and 24, illustrated in FIG. 4,

can, of course, also be used in the other three embodiments of the invention, at the proper location.

While specific embodirnents of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it Will be understood that the invention may be embodied otherwise Without departing frorn such principles.

What is claimed ist 1. In an electromechanical fluidic transducer having a flow feed line cornmunicating with two flow ontputs separated by a divider having a vertex, a single flow switching element oscillatably supported at said vertex and having a free end extending toward said flow feed line, said switching element being movable, under the influence of fluid flow and the diflerence in the pressures on its opposite lateral surfaces, into flow blocking relation in a selected one of said flow outputs; and at least one control signal responsive electrornagnetic device operable to select the flow output to control flow relative to a respective output; said switching element being lockable in its blocking position by an electrornagnetic device.

2. In an electromechanical fluidic transducer, as clairned in clairn l, adjustrnent canals cornrnunicating with opposite sides of said flow feed line and upstream from said switching element.

3. In an electromechanical fluidic transducer having a flow feed line cornrnnnicating with two flow outputs, two control signal responsive electrornagnetic devices operable to select the flow output, and each operable to control flow relative to a respective output; and a single flow switching element movable under the influence of fluid flow into flow blocking relation in a selected one of said flow outputs; said switching element being lockable in its blocking position by the associated electromagnetic device; a fork constituting said single flow switching element and having blade-shaped ends; said fork being mounted for oscillation abont a pivot in a manner such that its blade-shaped ends extend into the two flow outputs against the flow direction.

4. In an electromechanical fluidic transducer, as clairned in claim 3, said blade-shaped fork ends being so arranged that, at maximum lateral deflection, one blade-shaped fork end always engages an outer wall of a flow output, closing the latter completely, While the other blade-shaped fork end engages the inner Wall of the other flow output.

5. In an electrornechanical fluidic transducer, as claimed in clairn 4, electrornagnets arranged outside the flow outputs in proximity to the flow output Wall engaging position of said fork ends, said electromagnets constituting said control signal responsive electromagnetic devices.

6. In an electromechanical fluidic transducer, as claimed in claim 5, means rotatably mounting said fork substantially at the vertex of the two flow outputs.

7. In an electromechanical fluidic transducer having a flow feed line comrnunicating with two flow outputs, two control signal responsive electromagnetic devices operable to select the flow output, and each operable to control flow relative to a respective output; and a single flow switching element movable under the influence of fluid flow into flow blocking relation in a selected one of said flow outputs; said switching element being lockable in its blocking position by the associated electrornagnetic device; a leaf spring mounted substantially at the vertex of said flow outputs and constituting said single flow switching element; the free end 0f said leaf spring being notched in the shape of a fork.

8. In an electrornechanical fluidic transducer, as claimed in claim 7, said flow feed line being widened, upstream of said switching element, and symmetrically to the flow axis, by lateral displacement of its Walls outwardly to form shoulders.

References Cited UNITED STATES PATENTS 3l87762 6/1965 Norwood 13781.5 3,266,512 8/1966 Turick 13781.5 3276,463 10/1966 Bowles 13781.5 3,342,198 9/1967 Groeber 13781.5 3,494,369 2/1970 Inoue 13781.5X 3509,775 5/1970 Evans 137815X SAMUEL SCOTT, Primary Examiner