US2937608A - Ship stabilizer apparatus - Google Patents

Description

May 24, 1960 w. VANDERSTEEL SHIP STABILIZER APPARATUS L H m w v e R s E m mm .v E M O a WW w 8 A W 3 u w m a d v E 0%. 1:: E; 4 W H 7, Y m M d .m fin-I 3 Sheets-Sheet 2 W. VANDERSTEEL SHIP STABILIZER APPARATUS May 24, 1960 Filed May 7, 1958 I N V E N 7'0? M4 4 MM Kama/P5 7554 3y TORNEY y 4, 1960 w. VANDERSTEEL 2,937,608

SHIP STABILIZER APPARATUS Filed May 7, 1958 3 Sheets-Sheet 3 Fin Down Flu up INVENTOR Mun/u klwpe sresz.

ATTORNEY tates SHIP STABILIZER APPARATUS William Vandersteel, Bonnie Heights Road, Manhasset, N.Y.

Filed May 7, 1958, Ser. No. 733,660 9'Clain1s. (Cl. 114-126) atent A bilizers are referred to herein as activated fin stabilizers.

The present invention is particularly concerned with activated fin stabilizers, although certain features of the invention have a broader field of utility.

Ship stabilizing apparatus of the laterally projecting activated fin type was first suggested many years ago, but only in recent years has it reached a stage of practical development. Activated fin type stabilizers are now in use on many large ocean vessels and are being installed in an ever greater number. It is a necessary feature of any such stabilizing fin, that during times when its function is not needed, it be retractable into the hull of the vessel. Such retraction decreases hull resistance and also provides protection of the fin during maneuvering in harbors. One presently used retracting mechanism moves the fin endwise into a sea chest formed by suitable walls within the hull of the ship. Another known mechanism pivots the fin about a vertical axis, allowing the fin to retract into a horizontal slot or recess in the hull. Both of the mechanisms just described are designed to provide a rigid support for the fin when it is extended in the operating position.

Considerable ditficulty has been encountered with the presently available commercial stabilizing fins because of breakage, and subsequent loss of the fins in times of severe stress. This difficulty is inherent in a fin which is supported so as to be substantially rigid in its extended position. The breakage of fins during service conditions must be ascribed to their being subjected to overloads which cannot be properly calculated or anticipated.

One object of the present invention is to provide apparatus of the type described in which the fin mounting includes means for relieving the stresses imposed on the fin and its supporting structure under extreme overload conditions.

Another object is to provide apparatus of the type described in which the space requirements within the hull for the retracted fin and its operating mechanism are reduced as compared to the corresponding requirements of, the prior art devices.

Still another object of the invention is to provide a hinge-mounted fin havingthe hinge axis so disposed that the lift forces to which thefin is subjected create a moment about the hinge axis, which moment may be applied to control the angle of attack of the fin.

The foregoing objects are attained in the preferred structures described herein by providing a stabilizing fin which is retracted by rotation about an axis extending horizontally fore and aft of the ship, so that the fin retracts, by movement in a vertical plane into a recess in the side of the hull. However, as will presently appear,

2,937,608 Patented May 24, 1960 ice the disposition of the hinge axis may be other thanhorizontal provided that it is at an angle to a vertical, athwartship plane, whereby the lift forces encountered by the fin create a moment tending to rotate the fin bodily about its hinge axis. As will be understood, such moment is a maximum when the'hinge axis is horizontal or, in other words, is at 90 to the vertical, athwart-ship plane. Suitable operating mechanism is provided for maintaining the fin in the extended operating position and for retraction of the fin. By incorporating resilient means in that mechanism, the fin is given a controlled degree of freedom to deflect up or down in the event it is subjected to loading in excess of its design capacity. The resilient means may be so designed as to maintain the fin normally in a stable angular position with' respect to the retracting axis and to deflect from that position only when subjected to an overload.

The operating mechanism for retracting and extending the fin including the resilient means to provide strain relief are preferably situated inboard and may take a variety of forms, one of which is described herein.

The fin mounting includes a main shaft on which the fin turns for retraction and extension. This shaft is supported by two bearings located inboard and on respectively opposite sides of the fin Attached to each end of the main shaft are two crank arms which in turn are connected through strain relief devices to a motor means for moving the arms to retract and extend the fins. The strain relief devices resiliently hold the fin in the extended position and permit the fin to deflect from that position under conditions of excessive stress.

Other objects and advantages of the invention become apparent from a consideration of the following specification and claims taken together with the accompanying drawings.

In the drawings:

Fig. l is a horizontal sectional view through the hull of a vessel, showing a stabilizing fin and operating mechanism therefor in accordance with one form of the present invention, with the fin in its stabilizing position, part of the operating mechanism being shown in section;

Fig. 2 is a vertical section on the line 2-2 of Fig. 1.

Fig. 3 is a schematic view corresponding generally to Fig. l 'but showing a modified form and application of the invention.

' Referring now to Figs. 1 and 2 of the drawings, there is shown a fin 1 having a flap 2 pivotally mounted along its trailing edge. bolts 3 on the end of a cross shaft 4 which is journaled for rotation about its longitudinal axis in a yoke or housing 5. The housing 5, together with projecting trunnions 5a, forms a main or hinge shaft, generally indicated at 6, journaled in bearing'blocks 7 fixed to the frame of the ship. The housing 5 is located inside of the wall of a sea chest 8, which extends vertically upward as shown in Fig. 2 and is adapted to receive the fin 1, when the latter moves to its retracted position, shown in dotted lines in Fig. 2.

Two bearings 9 and 10 support the cross shaft 4 within the housing 5. A seal ring 11 on the housing 5 engages a fiat face on a flange on the shaft 4, thereby sealing the housing against the entrance of sea water. A pair of seal rings, one of which is shown at 12, are mounted'on the respective bearing blocks 7 and engage flat faceson the housing 5, thereby sealing the wallsof the sea chest against the leakage of sea water. These seals are shown somewhat diagrammatically and may be of any suitable construction for use with relatively rotating surfaces. Note that neither of the seals is required to'seal between two relatively sliding cylindrical members as is the case in certain of' the ship stabilizers of the prior art. The seal structures used may therefore be considerably simpler The fin 1 is mounted by means of 3 and are also more effectively than is the case with the socalled sliding fit seals.

The trunnions 5a project through the opposite sides of the bearing blocks 7 from'the wall of the sea chest. On the respective ends of the trunnions 5a, there are fixed, as by keying, a pair of crank arms 13. The opposite ends of the crank arms 13 are connected by pivot pins 20 to the ends of a pair of strain relief links generally indicated by the reference numeral 14.

Each strain relief link 14 (see Fig. 2) comprises a cylinder 15 pivoted by a pin 16 to a cross head 17. A piston 18 runs within the cylinder 15 and is provided with an aperture 18a extending between its two ends.

The piston 18 is biased to the center of cylinder 15 by a pair of opposed coil springs 31 and 32. The cylinder is filled with oil or other suitable hydraulic fluid. The piston 18 is fixed on a piston rod 19 pivoted at 20 to the outer end of one of the arms 13.

The cross-head 17 is apertured to receive rotatably an internally threaded sleeve which projects upwardly beyond the upper face of the cross-head 17 and carries on its outer periphery at that point a worm gear 25. The worm gear 25 mates with a worm 24 driven by a motor 26 mounted on a bracket 17a attached to the cross-head 17 and supplied with electrical energy from any suitable source. The worm gear 25 and its sleeve turn on a threaded fixed column 21, so that as the motor 26 runs the cross-head 17 is raised or lowered, thereby rotating shaft 6 and extending or retracting the fin 1.

The shaft 4 has mounted on its inner end a hydraulic servo-motor 27 enclosed in a cap 28 on the end of housing 5. The servo-motor 27 is supplied with hydraulic fluid from any suitable system through passages 29 and 30 drilled in the respective trunnions 5a and opening into ports inside the housing 5. By supplying hydraulic fluid to one or the other of the passages 29 and 30 by way of lines 31 or 32 and connecting the other line to a drain, the motor 27 may be rotated in either direction, as desired, to change the angle of attack of the fin 1.

The positioning of the flap 2 relative to flap 1 is well known in the art, and is used to reduce the angle through which the fin 1 must be tilted in order to achieve a desired stabilizing effect.

When the fin 1 is in its active or stabilizing position, which is shown in full lines in Fig. 2, it is effective, when the ship tends to roll, to apply to the water a thrust which is resisted by the water, thereby tending to reduce the rolling action. The upward or downward thrust on the fin 1 is translated into a torque tending to rotate the fin about the axis of the main shaft 6.

When the fin 1 tends to rotate about the hinge shaft 6, that rotation is opposed by one of the springs 31 and 32, depending upon the particular direction of rotation, and by the viscosity of the hydraulic fluid in the cylinder 15, which must flow through the passage 18a in order for the piston 18 to move relative to the cylinder 15. By selecting the springs 31 and 32 with a substantial spring rate, any movement of the fin 1 from its normal position may be prevented until the torque on the fin 1 exceeds a value suflicient to start compressing one of the springs. The piston 18 thereupon moves in the cylinder 15 allowing the fin 1 to pivot upwardly or downwardly from its normal position. The maximum deflection of the fin 1 from its active stabilizing position is determined by the construction of the strain relief link 14. In the arrangement shown, that deflection is determined by the points at which the springs 31 and 32 go solid, i.e., the position.

where their turns abut against each other. It is preferred to have this position reached when the fin 1 deflects approximately 20 in either direction from its nor mal stabilizing position. Such an arrangement effectively reduces the maximum forces to which the fin 1 and its supporting mechanism are subjected.

After the deflecting torque ceases, the springs 31 and 32 are effective to restore the piston 18 to its normal position at the center of the cylinder, and thereby to restore the fin to its normal position.

When it is desired to retract the stabilizer, the motor 26 is operatedrto run the parts to the position shown in dotted lines in Fig. 2, wherein the fin 1 lies within the sea chest 8. There is then no part of the stabilizer mechanism extending beyond the outline of the ships hull. It may be observed that the volume of sea chest required to contain the stabilizing apparatus within the outlines of the hull is of a minimum size, and presents no interference to the ships framing. Furthermore, most of the operating mechanism may be supported close to the sea chest, so that the space required within the ships hull for the entire apparatus is minimized.

In the Fig. 3 form of the invention, the parts having the same structure and function as those already described bear primed reference characters and require no further description (it being understood, of course, that the fin of Fig. 3 is mounted in a hull sea chest and is retractable into it, just as in the showing of Figs. 1 and 2).

In this form, a modified strain relief arrangement is indicated, piston 35 operating in a cylinder 36, which is filled with oil or other substantially incompressible fluid medium, the opposite ends of which cylinder are provided with spring-loaded relief valves 37, which are designed to blow at a predetermined limit pressure.

Furthermore, the Fig. 3 showing illustrates an extended application of the invention in which the lift forces encountered by the fin are utilized to effect changes in the angle of attack of the fin.

Provided the fin hinge axis is appropriately disposed, it will be seen that water action creating lift forces (so characterized in this art whether the net water action be upward or downward) will create a moment about the hinge axis of the fin; that is, they will tend to rotate the fin bodily about its hinge axis, such moment normally being counteracted by the strain relief means as above described. As will be apparent, too, such a moment is created not only when the hinge axis is disposed hon'- zontally in a fore and aft plane as illustrated, but whenever the axis is other than aligned with the line of action of the lift forces. Assuming the net lift forces to act substantially vertically, it is obvious that the moment is zero if the hinge axis of the fin is disposed in a vertical, athwart-ship plane, the moment increasing as the hinge axis is tilted fore-and-aft with respect to such a plane and reaching the maximum when the axis is disposed horizontally, as shown.

While this feature of the invention lends itself to embodiment in a great variety of forms, a schematic showin of one simplified form only is illustrated.

According to this showing, the upper and lower ends of cylinder 36 are connected by flexible tubes 40, 41 (of very small cross section compared to that of cylinder 36) to the opposite ends of a servo cylinder 42 housing a piston 43 the movement of which is opposed by suitable springs 44, 45. By this means, the lift forces sensed by the fin are translated, as a function of increased oil pressure at one end or the other of cylinder 36, to change the position of piston 43 in its cylinder 42.

The rod 46 of piston 43 is connected to the upper end of a so-called hunting rod 50, the lower end of which is connected by rod 51 to the ship motion sensing device indicated at 52. Such a device is well-known in the art and since, per se, it forms no part of the present invention, it requires no detailed description. The function of the sensing device, of course, is to dictate the lift requirement of the fin in accordance with the usual gyro and other data supplied to it.

Intermediate its ends, the hunting rod is connected by rod 53 to the control crank 54 of the fin tilting apparatus 55, that is, the apparatus which serves to change the angle of attack of the fin, as directed by and in accordance with the movement of the mid-point of the hunting rod. This apparatus, again, may be of any well-known or preferred form but for present purposes, 55 may be assumed to comprise a variable displacement hydraulic pump serving to supply hydraulic fluid underpressure to line 31 or line 32' and at a varying rate, depending upon the disposition of control crank 54.

Thus, regardless of the position of the hunting rod as dictated by the sensing device 52, the servo mechanism 42-46, responsive to the moment created by the action of the lift forces on the hinged fin, is efi'ective to control the means for changing the angle of attack of the fin, in this instance the pump means 55.

In the light of the foregoing exemplification of the principles of the invention, the following is claimed:

1. Apparatus for stabilizing a ship against rolling, comprising a fin, a main shaft supporting said fin and rotatable about an axis extending parallel to the ship's side and just inside the hull, said shaft and fin being movable between an operating position wherein the fin projects laterally from the hull and is subjected to torque about said axis when the ship tends to roll, and a retracted position wherein the fin extends parallel to the hull, motor means, means connecting said motor means to said shaft for rotating it between its operating and retracted positions, strain relief means in said connecting means to permit limited angular motion of said shaft under the influence of said torque without moving said motor means, a housing fixed on said main shaft, and a cross shaft journaled in said housing and carrying said fin for rotation about an axis extending at right angles to said main shaft.

2. Ship stabilizing apparatus as defined in claim 1, including bearing means in said housing supporting said cross shaft, and rotary seal means protecting said bearing means against the entrance of sea water.

3. Ship stabilizing apparatus as defined in claim 2, including a fluid servo-motor in said housing to rotate said cross shaft and fluid supply lines extending to said servomotor, through said main shaft and said housing.

4. Apparatus for stabilizing a ship against rolling, comprising a fin, a main shaft supporting said fin and rotatable about an axis extending substantially parallel to the ships side and just inside the hull, said fin and shaft being movable between an operating position wherein the fin projects laterally from the hull and is subjected to torque about said axis when the ship tends to roll, and a retracted position wherein the fin extends parallel to the hull, walls defining a seat chest inside the outline of the hull to receive the retracted fin, said shaft projecting through the walls of said sea chest, rotary seal means between said shaft and said walls, motor means, means connecting said motor means to said shaft for rotating it between its operating and retracted positions, said connecting means comprising crank arms on the shaft inside the hull, and strain relief means in said connecting means to permit limited angular motion of said shaft under the influence of said torque without moving said motor means.

5. Apparatus for stabilizing a ship against rolling, comprising a fin, a main shaft supporting said fin and rotatable about an axis extending parallel to the ships side and just inside the hull, said shaft and fin being movable between an operating position wherein the fin projects laterally from the hull and is subjected to torque about said axis when the ship tends to roll, and a retracted position wherein the fin extends parallel to the hull, motor means, means connecting said motor means to said shaft for rotating it between its operating and retracted positions, strain relief means in said connecting means to permit limited angular motion of said shaft under the infiuence of said torque without moving said motor means, a housing fixed on said main shaft, a cross shaft journaled in said housing and carrying said fin for rotation about an axis extending at right angles to said main shaft, means in said housing for applying torque to said cross shaft, walls defining a sea chest inside the outline of the hull to receive the retracted fin, said main shaft projecting through the Walls of said sea chest, rotary seal means between the main shaft and said walls, said main shaft having apertures extending therethrough from inside the hull through said walls and communicating with the interior of said housing, and means extending through said apertures and controllable from inside the hull for actuating said torque applying means.

6. In a ship stabilizer apparatus of the kind including a fin, a fin shaft supporting the same and power means for rocking the fin about the axis of its support shaft and thereby changing the angle of attack of the fin, the improvement which comprises hinge support means for the said fin and fin shaft adapted to permit bodily movement of the fin and the fin shaft about the axis of the hinge support means, the hinge axis being so positioned that the lift forces acting on the fin create a moment about such axis, and transmission means for applying such moment to activate the said power means and thereby rock the fin about the first-mentioned axis.

7. In a ship stabilizer apparatus of the kind including a fin, a fin shaft supporting the same and power means for rocking the fin about the axis of its support shaft and thereby changing the angle of attack of the fin, the im provement which comprises hinge support means for the said fin and fin shaft adapted to permit bodily movement of the fin and shaft about the hinge axis of the support means, the hinge axis being so positioned that the lift forces acting on the fin create a moment about such axis, and transmission means for applying such moment to activate the said power means and thereby rock the fin about thecfirst-mentioned axis, said transmission means including yieldable means normally restraining the fin and shaft against bodily movement about the said hinge axis.

8. In a ship stabilizer apparatus of the kind including a fin, means mounting the same for rotation about a laterally projecting axis for varying the angle of attack of the fin, thereby to create roll-reducing thrust, and power means for rotating the fin about its said laterally projecting axis, the improvement which comprises hinge support means for the said fin adapted to permit bodily movement thereof about a second axis, the latter being disposed at an angle to a vertical athwart-ship plane, whereby the lift forces encountered by the fin create a moment tending to rotate the fin bodily about the said second axis, and transmission means for applying such moment to activate the said power means and thereby rotate the fin about the laterally projecting axis.

9. In a ship stabilizer apparatus of the kind including a fin, means mounting the same for rotation about a laterally projecting axis for varying the angle of attack of the fin, thereby to create roll-reducing thrust, and power means for rotating the fin about its said laterally projecting axis, the improvement which comprises hinge support means for the said fin adapted to permit bodily movement thereof about a second axis, the latter being disposed horizontally in a fore and aft plane, whereby the lift forces encountered by the fin create a moment tending to rotate the fin bodily about the said second axis, and transmission means for applying the said moment to activate the said power means and thereby rotate the fin about the laterally projecting axis.

References Cited in the file of this patent UNITED STATES PATENTS 2,223,562 Giliberty Dec. 3, 1940

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