US2465285A - Fluid current driven apparatus - Google Patents

Description

March 22, 1949. w, SCHWlCKERATl-l 42,465,285

FLUID CURRENT DRIVEN APPARATUS Filed Dec. 25, 1944 l 2' sheets-sheet 1 Afrox/v March 22, 1949. W, SCHWlCKRA'l-H 2,465,285

I FLUID CURRENT DRIVEN APPARATUS 2 Sheets-Sheet 2 Filed Dec. 23, 1944 /A/vfA/TOR Patented Mar. 22, 1949 FLUID CURRENT DRIVEN APPARATUS Werner Schwickerath, Vereeniging, Transvaal, Union of South Africa Application December 23, 1944, Serial No. 569,605 In the Union of South Africa January 22, 1944 15 Claims.

This invention relates to apparatus driven by a fluid .current such as the wind or water Iiowing in a materially level channel: said apparatus being of the kind in which a vane is mounted on a support constrained for movement transverse to the current, the vane being inclined to the current to derive transverse driving force from the latter and thereby drive itself and its support transversely to the current. A convenient arrangement is that in which the transverse movement is reciprocatory, in which case the apparatus includes means to reverse the inclination of the vane to the current upon the vane and its support arriving at each prescribed limit of their reciprocating movement; causing the current to drive the vane and its support alternately in opposite directions across the current. The vane support is connected to mechanism which makes use of its reciprocating movement.

When motion rather than power is the desired object as in the case of a oW meter, the vane may be of the flat plate type operating by reaction; but when power production is the object, the vane would in practice be an aerofoil which develops denite aerodynamic lift.

In such apparatus it is desirable for the inclination of the vane to be adjusted according to the ratio of the current velocity to the velocity of the vane across the current. In particular, it is desirable from the point of View of obtaining the maximum power from the current, that the true angle of incidence to the current should be maintained constant.

In the diagram, Figure VIII of the accompanying drawings, if the vector A represents the velocity and direction of the current, and B that of the Vane across the current, the velocity and direction of the current relative to the vane is represented by C. If a is the optimum angle of incidence of the vane to the current, and b is the inclination of the vane to the horizon and it is desired to maintain a at more or less constant value, the angle b has to be adjusted approximately as the ratio A/B varies. It is a principal object of the invention to provide mechanism by which this adjustment is automatically achieved, Y A further object of the invention is to provide mechanism including a servo-aerofoil adapted to make such automatic adjustment: to eiect the periodic reversals of the inclination of the vane; and to govern the speed of the apparatus in high winds. The servo-aerofoil is also capable of statically counterbalancing the vane in so far as the latter is out of balance about its tilting axis.

According to the invention, apparatus as above described comprises a vane for exposure to the current, a support which constrains the'vane for movement across the current, the vane being pivoted to the support to vary its inclination to the direction ofthe current, aservo-aerofoil pivotally mounted for displacement by the current transversely to the latter, and motion-transmitting mechanism between the vane and the servo-aerofoil comprising a parallel-motion linkage of which one element is provided on the vane and the parallel element is linked to the servo-aerofoil, the mechanism acting to hold the vane to a substantially constant angle of incidence relatively to the current during movement of the vane across the current.

The servo-aerofoil is preferably of symmetrical profile possessing both high lift characteristics and high drag characteristics. Said servo-aerofoil is so mounted on a frame as to be displaced by the current across the latter, and is connected to the Vane to tilt the latter from its position of zero inclination according to the displacement of the servo-aerofol from a position of Zero displacement. Y

The invention includes means whereby the arrival of the reciprocating vane and the vane support at the ends of their reciprocatory path causes the inclination of the servo-aerofoil to the current to be reversed, so that its displacement is reversed, causing in turn reversal of the inclination of the vane.

According further to the invention apparatus as described is governed against overspeeding by means causing diminution of the above mentioned active torque, upon the current pressure becoming excessive. In one arrangement for this purpose the servo-aerofoil is capable of being displaced from its normal working position to a governing position by the drag exerted on it by the current, and against the resistance of an initially loaded spring. When the servo-aerofoil is in such governing position, its capacity for setting up the active torque on the vane is diminished, as by lessening its own inclination to thel current.

An example of the invention constructed as a wind motor for directly driving a vertical reciprocating pumpis shown in the accompanying drawings in which Figure I shows the motor of the inventionerected on its mast.

Figure II is a similar but more detailed view drawn to a larger scale. Figure III is a plan of the servo-aerofoil detached from the motor framework.

. Figure IV is an end view of Figure III.

Figure V is a plan view identical with Figure III butv showing the servo-aerofoil swung back.

. Figure VI is an end View of Figure V.r

Figure VII is a much enlarged horizontal section through the servo-aerofoil.

Figure VIII is the diagram already referred to. 2 indicates the mast, stayed by guys 3, on which the motor is mounted at an elevation above the ground, The pump rod 4 extends up through the axis 45. Said torsion rod 49 is secured by its screw threaded end 50 and lock nut 5| to a head 52 mounted at the end 53 of the shaft 42 and rotatable relatively to said shaft. Said head 52 is attached by the pivot pin 54 to the internal framework 55 of the servo-aerofoil so as to tilt the latter about the axis 56 of the shaft 42 and the rod 49.

Another feature of the servo-aerofoil 40 is that it is capable of bodily movement in its own plane from a normal working position to any of a range of governing positions. This bodily movement is a swinging back movement about the axis 51 of the pivot pin 54, which axis is perpendicular to both the axes 45 and 56. To permit this movement, the end 58 of the servoaeroioil through which the shaft 42 enters is formed with an elongated gap 59. Said end 58 is shaped in plan as an arc about the axis 51.

A rigid extension 60 of the fork 43 carries a. roller 6I which extends into the gap 59, so as to be between the edges 62 of the latter and act as a stop limiting the extent of the tilt of the servo-aerofoil on either side of its position of zero tilt. Said gap 59 tapers in width in the direction from the leading edge 63 to the trailing edge 64 of the servo-aerofoil.

The tendency to swing bodily as described is set up by the drag of the wind on the servoaerofoil and particularly on the spherical enlargement 4| which is positioned at the outer end of the servo-aerofoil to gain leverage. This tendency is yieldingly resisted by the spring 65 which is attached at one end to the head 52 and at the other e'nd to the framework of the servoaerofoil and is arranged to exert on the latter a moment about the axis 51 contrary to the moment exerted by the sphere 4I, and normally holding the servo-aerofoil in the normal working position of Figure III; in which it is stabilized by its rib 66 pressing against the stop 61 extending from the head 52. In said normal position the centre of pressure 68 of the servo-aerofoil is, in plan, in the axial line 56 of the hollow shaft 42.

The three operations in which the servo-aerofoil takes part are performed as follows:

Periodical reversal of the main aerofoiLAs sume the motor to be in the Figure I position and the rocking beam 1, with the main aerofoil I2, to be rising. They are rising because the main aerofoil is inclined upward to the wind, and is subjected by the latter to positive lift.

The aerofoil I2 is retained in that tilted position by the servo-aerofoil which is also tilted up to the wind and derives lift force from the latter, which force it applies through the linkage 48. 41, 22. 2| and 20 to the arm I9.

Upon the cam edge 21 coming level with the pin 34 the lever 3|, 32 rocks over, impelled by its spring 31 and thereby tilts the servo-aerofoil 40 downward about its axis 56 so that the servoaerofoil derives downward lift from the wind. This lift force is transmitted through the aforesaid linkage to reverse the incidence of the main aerofoil I2 (Figure II) so that wind drives the main aerofoil downward. The elastic yielding of the torsion rod 49 permits lthe lever 3|, 32 to snap over While the servo-aerofoil follows somewhat more slowly.

Setting of the vane to optimum angle of lift.- As already stated, the axis I 6 about which the aerofoil I2 is mounted to tilt, is in front of the centre of pressure I8 of said aerofoil, so that the wind pressure tends always to tilt said aerofoil I2 to its position of zero incidence. I'he same wind however acts on the servo-aerofoil 40 and tends to impart to the latter the semaphore displacement which, through the above mentioned linkage 46 to I9, increases the angle of incidence of the main aerofoil irrespective of whether the lift of the latter is upward or downward. The actual angle of incidence assumed by the main aerofoil I2 thus depends upon the balance of those two oppositely acting forces.

In making its reciprocating strokes, the main aerofoil I2 acquires velocity across the wind Iwhich diminishes its true angle of incidence to the wind; and is correspondingly less influenced by the direct tendency of the wind to tilt it towards zero incidence. This reduces the opposition of the main aerofoil to the :tilting torque actively exerted on it by the servo-aeroioil 40. The latter shifts to a further position along its semaphore path and correspondingly tilts the main aerofoil to a greater angle of incidence, at which balance is again arrived at. The servo-aerofoil, having no material velocity across the Wind, is not sensibly aie'cted by Variation of the A/B ratio.

Governing-The last described action of the servo-aeroioil tends always to cause the main aerofoil to take the maximum of the power cffered -to it by the wind; and it is accordingly necessary to limit the power intake when that oiTered is excessive and would lead to unduly high rate of recinrocation of the rocking beam 1 and main aerofoil I2.

The spring 65 is so initially tensioned that it will not yield to the moment due to the wind pressure on the sphere 4I, until said pressure becomes excessive. When that occurs the spring 65 yields and allows the servo-aeroioil to swing back towards the Figure V position.

One result is that the aerofoil prole virtually changes progressively to the form suggested in Figure VI, which has a lower lift characteristic and the aspectratio is diminished as in Figure V. The active force exerted by the servo-aeroioil to tilt the main aeroioil is diminished, allowing the bias of the latter to diminish its angle of incifence, so that its speed is prevented from rising unduly.

Another result is that the centre of pressure 68 swings out of the axis 56 to a position behind said axis as indicated in Figure V. So long as 68 was alined with axis 56, the wind pressure on the servo-aerofoil had no influence on lthe angle of incidence of the latter; but upon 68 coming behind 56, the servo-aerofoil assumes the biassed condition of the main aeroioil I2 in which the Wind tends to diminish its angle of incidence. This again causes the active torque on the main aerofoil I2 to be progressively diminished as the servo-aerofoil progressively swings back. The elasticity of :the torsion rod 49 enables this to occur although lever 3 I, 32 remains stationary.

It is preferred to employ positive mechanical means for progressively limiting the angle of incidence of the servo-aerofoil. When the servoaerofoil is in the normal working position of Figures III and IV, the roller 6I is within the widest portion of gap 59 and the servo-aerofoil is free to tilt either way from its Zero position to the full extent required to give it the lift necessary to control the main aerofoil I2. As the servoaerofoil progressively swings back to the position of Figures V and VI, the roller 6I comes into gradually narrower sections of the gap 59 so that the angle'through which the servo-aerofoil can tilt is diminished more and more until the servo- 7 aerofoil is yxed in the position@ Zero incidence by, the-rollerk 6 l` comme into the. small end 69. of the gap 59.

When Athe vane I2 is actuated by a Water current, `it is convenient to arrangeit aswell `as the servo-aerofoil to reciprocate horizontally.

I claim:

1. ,.Current driven apparatus comprising a vaine for ,exposure to the current', a support which con strains the vane forgmovement-across thecurrent, the vane being pivoted to the supportto allow it to vary its inclination tothe direction of the current, a servo-aerofoil pivotaliy mounted for displacement by the currenttransversely to the latter, and motion-transmitting mechanism between the -vane and the servo-aerofoil comprising a par-- allel-motion linkage of which one element-isprovided on the vane and the parallel element vis linked to the servo-aerofoil, the mechanism acting-to hold the vane to a substantially constant' angle of incidence relatively to the current during movement of the vane across the current.

2. The apparatus claimed in claim 1, in which the movement of the vane-support and the vane across the current is a, reciprocating movement,

and comprising means, rendered operative by approach of said parts to the ends of their reciprocatory path, Yto reverse the incidence of the servoaerofoil lto the current, whereby the transverse displacement of the servo-aerofoil is reversed and reverses the incidence of the vane to the current.

3. Current driven apparatus comprising yan,

said angle', and means preventing drag movement at current velocities below a predetermined velocity.

4. Current driven apparatus comprising a vane for exposure to the current, a support which constrains the vane for movement across the current, the vane being pivoted to the vsupport to vary its inclination to the direction of the current, and a servo-aerofoil pivotally mounted for displacement by the current transversely to the latter, and motion-transmitting mechanism connecting the servo-aerofoil and the vane whereby displacement movement of the aerofoil and tiltingmovement of the vane are positively dependent on one another.

5. Current driven apparatus comprising a vane for exposure to the current, a vane support mov.- able about a xed axis, which support constrains the vane for movement across the current, theV vane being pivoted to the support to vary its inclination to the direction of the current, said vane being biassed towards the position of zero inclination to the direction of the current, and a servo-aeroioil pivotally mounted for displacement by the current transversely tothe latter, the apanism comprising a parallel-motion linkage or"v which ,one element is provided on the vane and theralalcl, .elementis .movable aboutsaid 8 and-,of which the `supportis the third element; and a motion-transmitting link -between'therst named two elements the fourth; the mechanism acting to hold thevaneto a substantially constant angle of incidence relatively to the current dureing movement of the vane-across the current.

6. Current driven apparatus comprising a vane support reciprocable across the current, avant mounted on said support to share its reciprocating movement and pivoted on said support for. adjustment of its inclination to the current,:a servo-,aerofoil exposed to the current, motion:1 transmitting mechanism connecting `said servo-i aerofoil and said vane whereby movements of :the servo-aerofoil are transmitted to said vane. and means, rendered operative byapproachotA said -vane and vane support to the ends of their reciprocator-y path, to-reverse 'the incidence1 of the servo-aerofoil to the current, 'whereby Lthe'. transverse displacement of the servo-aerofoilis reversed and reverses the incidence of the vane'4 to the current, said reversing means comprising. cam and Va cam follower only one of whichre-` ciprocates with the vane support, vthe 4cam provid-z ing for the follower a circuit with dimensions par-- allel to thel reciprocatory path of the vane sup port and transverse thereto, thel dimension par-: allel to the reciprocatory lpath controlling theextent of said path and the relative cam tofollowex` movement in the other dimension governing sim-` ilar movement of the follower to-cause said reversalof the inclination ofI the servo-aerofoil.

7. Current driven apparatus comprising the combination of a frame, a beam pivoted on :the frame to oscillaterelatively thereto, a lvane plv-4 otallyv mounted on the beam to oscillate there-A with and so as to be tiltable about an axis trans-z verse to the length of the beam and thereby alterits inclination to the current, a servo-aerofolt pivotally mounted on the frame to be .displaceable transversely to the current and also tiltable about an axis parallel Ywith its length to alter its'angleY of `incidence to the ciu'rent, and mechanism for tilting the servo-aerofoil about said axis, saidl mechanism comprising a part movable bodily rela-` tively to the frame and a part movable bodily with the aerofoil about the axis of said pivot, and a, universal joint connecting said parts for motion transmission irrespective of displacement of the servo-aerofoil relatively to the frame, the apparatus also comprising motion transmission mech anism whereby the transverse displacement ofthe servo-aerofoil varies the inclination ofthe vane to the current.

8. Current driven apparatus comprising a vanesupport, a vane carried by said support for exposure to the current and movement across the latter, and pivoted to said support for adjustment otits inclination to the current direction and biassed towards the position of zero inclination tothat direction, and means comprising an ele-i4 exerts on the vane an active torque about the axis of the vane tending to increase its inclination to the direction of the current so that the* actual inclination to that direction assumed by the vane at any instant is that due to the balancev of the biassing force and the active torque acting on it atthat instant, said apparatus also comprising means governing the apparatus against over-V speeding, said means being arranged to cause diminution ofthe active torque when the speed` limit. is exceeded.

9. Current driven apparatus comprising a vane support, a vane carried by said support for exposure to the current and movement across the latter, and pivoted to said support for adjustment of its inclination to the current direction and biassed towards the position of zero inclination to that direction, and means comprising an element directly movable by the current, and motion-transmitting mechanism connecting said element and said vane whereby said element exerts on the vane an active torque about the axis of the vane tending to increase its inclination to the direction of the current so that the actual inclination to that direction assumed by the vane at any instant is that due to the balance of the biassing force and the active torque' acting on it at that instant, said element `being a servo-aerofoil pivotally mounted for displacement by the current, and arranged so to be influenced by current pressure in excess of a predetermined value as to diminish the active torque it exerts on the vane.

10. Current driven apparatus comprising a vane support, a vane carried by said Support for exposure to the current and movement across the latter, and pivoted to said support for adjustment of its inclination to the current direction and biassed towards the position of zero inclination to that direction, and means comprising a servo-aerofoil pivotally mounted for displacement by the current transversely to the latter and for tilting movement to vary its inclination to the current and connected to said vane for exerting on the vane an active torque about the vane axis tending to increase the inclination of F7 the vane to the direction of the current so that the actual inclination to that direction assumed by the vane at any instant is that due to the balance of the biassing force and the active torque acting on it at that instant, said aerofoil being also arranged to be so influenced by current drag in excess of a predetermined value as to diminish the active torque it exerts on the vane and being for this purpose mounted for bodily movement, by the drag of the current on it, from a normal working position to any of a range of governing positions, the arrangement comprising an initially loaded spring tending to retain the servo-aerofoil in a normal working position, the governing position taken up by the servoaerofoil under the influence of excess drag being determined -by the balance of the current drag on said servo-aerofoil and the resisting pressure of said spring.

11. Current driven apparatus comprising a vane support, a vane carried by said support for exposure to the current and movement across the latter and pivoted to said support for adjustment of its inclination to the current direction, and means tending to influence the inclination of said vane, said means comprising a. servo-aerofoil pivotally mounted for displacement by the current transversely to the latter and for tilting movement to vary its inclination to the current, said servo-aerofoil being also mounted for bodily movement, by the drag of the current on it, from a normal working position to any of a range of governing positions, the apparatus comprising an initially loaded spring tending to retain the servoaerofoil in a normal working position, the governing position taken up by the servo-aerofoil under the influence of excess drag being determined by the balance of the current drag on said servoaerofoil and the resisting pressure of said spring.

12. The apparatus claimed in claim 11, in which the servo-aerofoil is mounted to tilt about an axis parallel to its length, and including means rendered active by a movement of said servo-aerofoil towards a governing position, said means tending to tilt it about said axis is the direction to diminish its incidence to the current.

13. The apparatus claimed in claim 1l, in which when the servo-aerofoil is in its normal working position, its centre of pressure is coincident with its tilting axis, and the bodily movement to a governing position displaces the centre of pressure, thereby causing the current drag to exert a moment on the servo-aerofoil tending to tilt the latter towards its position of zero incidence.

14. Current driven apparatus comprising the combination of a frame, a beam pivoted on the frame to oscillate relatively thereto, a vane pivotally mounted on the beam to oscillate therewith and so as to be tiltable about an axis transverse to the length of the beam and. thereby alter its inclination to the current, a servo-aerofoil so pivotally mounted on the frame as to be displaceable transversely to the current and also tiltable about an axis parallel with its length to alter its angle of incidence to the current, means operated by the rocking of the beam, and arranged to reverse the incidence of the servo-aerofoil to the current and thereby to reverse the direction of the transverse displacement of the servo-aerofoil in synchronsrn with the oscillation of the beam, and motion-transmitting mechanism between the servo-aerofoil and the vane whereby the transverse displacement of the servo-aerofoil causes variation of the inclination of the vane to the current.

15. In a stationary apparatus suitable to be driven by a fluid current an arrangement comprising an aerofoil of curved profile, means allowing displacement of said aerofoil by the current transversely to the latter, means allowing tilting movement of said aerofoil to vary its angle of incidence relatively to the current, a servoaerofoil pivotally mounted for displacement by the current, means connecting the aerofoil and the servo-aerofoil whereby movements of the servo-aerofoil are transmitted to the aerofoil, and further means allowing bodily movement of said servo-aerofoil, by the drag of the current on it, from the normal working position of the servo-aerofoil transverse to the current, in a direction substantially parallel to the direction of the current, and elastic means tending to maintain said aerofoil in said normal working position.

WERNER SCHWICKERATH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 237,851 Faskett Feb. 15, 1881 276,939 Trumble May 1, 1883 804,676 Roeh Nov. 14, 1905 1,221,090 Prewitt et al Apr. 3, 1917 1,490,787 Thornycroft Apr. 15, 1924 2.151.172 Villarreal Mar. 2l, 1939

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