US1894272A - Ship stabilizer - Google Patents

Description

`Ian. 17', 1933. H, HORT 1,894,272

SHIP STABILIZER Filed Feb. 17. 1931 Patented Jan. 17, 1933 UNITED STATES PATENT trici:

HERMANN HORT, OF BERLINfNEU-WESTENID, GERMANY, ASSIGNOR TO GESELLSCHAFT FUR ELEKTRISCHE APPARATE, F. MARIENFELDE NEAR BERLIN, GERMANY, A

CORPORATION OF GERMANY SHIP STABILIZER Application led February 17, 1931, Serial No. 516,351, and in Germany February 24, 1930.

Mthe longitudinal axis of the ship. The conl0trol of the driving motor for the bogie or truck or for the pump conveying the liquid takes place in `dependence on the size or speed of the deflections or the angle of roll i. around the position of equilibrium of the ship.

lThe oower retuired for acceleratinff the stabilizing or balancing masses and the fact that at a medium roll. of the ship the roll angle deflections toward port and starboard .respectively are of different size are not QG'taken into account in this method of control so that this control is inaccurate and not sufficiently dependable.

According to my invention one or a plu- ...iality of electric motors, which drive the stabilizing' bogies or the pumpsA and blowers for propelling the masses of liquid of stabilizing tanks, are likewise regnlatable in dependence on the size or the speed of the roll ,l Aof the ship in such a manner that in case of periodic rolling of the ship they effect a peri* odio shifting of the stabilizing or balancingr masses, which inrelation to the rolling of the ship is shifted in phase by anangle of about ..--O'OO. y rlfhe motorsare, however, additionally. regulated by further control members which bring about a premature change-over of the motors as required for thekacceleration ofthe stabilizingr masses and for obtaining` the i phase shift of 90Q necessary for an eiiicient i0 damping. There are, furthermore, provided control members for the motors adjustable in dependence on the travel of the bog-ies, in or` der to enable wrong one-sided positions ofthe v H,loo,g:ies to be compensated as well as any mean it-'oblique positions ofthe ship. By changing the polaritv for instance of the armature terminals ofthe motor, theresult may be at-` tained that the motor controls the stabilizing masses driven byit in suchva way that their motion in relation to the periodic roll of the ship either lags behind in phase by about 90o or leads by about 90. In the first case the masses effect a stabilization of the roll, as is well known, while in the latter case they increase the rolling of the ship and thus bring about an artificial swaying of the ship as occasionally required for practice or for testing purposes.

An embodiment of my invention is by way of example illustrated in the drawing annexed to my specification and forming part thereof.

' In the drawing Fig. 1 shows a diagram of connections for the control of a motor, and

F ig. 2 a perspective view of a damping device employed in my system of control.

Referring to Fig. 1 of the drawing, it will be observed that the armature current of the driving motor 1 of the bogie is regulated by a controller-type switch 2, 3. The contacts 3 of the controller are through resistances 4.- and 5 of different strength connected in the usual manner to the positive and negative poles respectively of a direct current supply.

The switch arm 2, which is shown in the change-over position for the motor 1, is turned through the bevel wheels 7 and 8 from the differential shaft 9. To the diderential gear 10 there is on the one hand transmitted the 'true value of the angle of roll by the follow-up motor 12, which follows the roll angle indicator 11, suchtransmission being eiected by the bevel wheels 13, shaft 14 and bevel wheels 15. On the other hand, the true value of the rolling-angle is also transmitted, by bevel gears 16, to a damping device indicated at 17 in Fig. 1, the details of said device being shown in Fig. 2 and described below. In a mannerset forth hereinafter, said damping device transmitsa portion of this angular motion, with a certain time lag, to thedifferential gear 10, by means of bevel wheels 19 and 20. The switch arm 2 will then take a position corresponding to the difference of` the motions transmitted to the differential gear 10 by the bevel wheels 15 and 2O respectively.

The exciter winding 21 of the motor l is connected in circuit between the positive pole and the neutral wire of the direct current network 6. In series with it are connected two rheostats 22 and 23. If a plurality of bogies arranged side by side are employed, their respective travel would naturall be of unequal length, on account of the di erence in friction along the tracks, and the object of the rheostat 22 is to equalize such travel. In the case of equal lengths of travel of the bogies at both sides of the vessel, the rheostat 23, adjustable by hand on starting, is short circuited through the armatures 24 and 25 of the relays 24 and 25 and through their connecting lead 26. The driving motor 1 mounted on the bogie transmits its motions, which correspond with the travels of the bogies, by means of an electric teletransmission system having a ytransmitter 27 and a receiver 28, to a damping device 30 of the same character as 'the damping device 17, said receiver 28 controlling a motor 29 which follows up or reproduces the motion of the receiver. By means of bevel wheels 31 and 32, the damping device 30 transmits to a switch disc 33 connected with the wheel 32, a movement which is of less extent than that of the follow-up motor 29 and shifted `in phase relatively thereto by about 90. This disc 33 carries a conducting slide member 34 through which the stationary contact 35 is permanently connected to the positive conductor of the direct current network. In case of equal movements of the bogies at both sides of the vessel the damping device 30 transmits to the switch disc 33 very small hunting motions only so that the slide member 34 does not come in contact with the stationary contacts 36 and 37. The latter are connected by wires 38 and 39 respectively, to the slide contacts 4() and 41 at the controller switchboard; two further slide contacts and 41 are connected by wires 42 and 43 respectively to the exciter windings of the relays 24 and 25. The two pairs of slide contacts 40, 40 and 41, 41 are short circuited by the brush 44 mounted upon and insulated from the controller switch arm 2, when the said arm is moved across these contacts.

Fi 2 shows, as an example, a construction -whic may be adopted for the damping devices 17 and 30. The inner end of a spirally coiled leaf spring 45 is secured to a shaft 46, its outer end to a spring housing 47. The shaft 46 corresponds to the shafts shown in Fig. 1 to the left of the devices 17 and 30 respectively. To the spring housing 47 is secured rigidly the shaft 48 which transmits the resulting motion, said shaft 48 corresponding to those which in Fig. 1 extend to the right of the devices 17 and 30. The housing 47 further has two arms 51 and 52 at diametrically opposite points, and with these arms are connected pivotally the rods of two pistons mounted to slide in hydraulic cylinders 49 and 50 respectively which are connected by a conduit 53 controlled b an adjustable throttle valve 54. Prefera ly, two springs coiled in opposite directions are arran d side by side in the housing 47, in order to o tain an accurate setting of the damping device to its zero osition.

The damping evice operates as an accumulator of angular movements in which the periodic movements of the shaft 46 (corresponding, for instance, to the rolling movements of the ship, transmitted by the followup motor 12, Fig. 1) are accumulated and then delivered with a time lag. Only when the valve 54 is fully open, no damping action will take place, so that in this special case the movements of the shaft 46 will be transmitted to the shaft 48 in their full extent and without any time 1a However, in the case... of the damping devices 17 and 30 of Fig. 1, the valve 54 is set to produce a strong throttling action, so that the periodic movements of the shaft 48 will be of much smaller extent than those of the shaft 46, and that furthermore, and this is very important, the movements of the shaft 48 will lag in phase by about 90 behind those of the shaft 46.

To explain the operation of the apparatus shown in Fig. 1, let us assume that there are several ship-damping trucks to be propelled in one direction or the other on parallel tracks extending athwart the ship. Each of these trucks would have a driving motor 1, the armature circuits of all of these motors being connected with a single'switch or controller 2, 3. It is not absolutely necessary that the field circuit be controlled according to the length of travel of each truck. When such a regulating mechanism for controlling the field circuit is used, as indicated at 21- 43, a separate mechanism of this character must be provided for each of the truck motorsE In describing the operation I shall, for the time being, disregard the regulation of the field circuit.

If the damping device 17 were omitted, the rolling motion of the ship would cause the controller arm or switch arm 2 to be deflected from the median position illustrated, in synchronism with the deections of the roll angle indicator 11. Thus the driving motor 1 of each truck will be energized for rotation in one direction when the switch arm 2 is thrown to the left, and in the other direction when said switch arm is thrown to the right. The motors will therefore be reversed whenever the switch arm 2 passes through the central or median osition illustrated. At this moment, the truc s will remain stationary, and this will occur at a time when the trucks on the higher side of the ship have reached the point at which the direction of their travel is to be reversed. When the ship during its rolling motion passes through its horizontal position (at which moment the angular velocity of the rolling motion is greatest) the trucks on the higher side of the ship will remain stationary; on the other hand, the trucks will cross the longitudinal center line of the ship with theiry maximum velocity at the moments the rolling motion of the ship is reversed. rlhus the periodic movements of the trucks will lag in phase behind those of the roll angle indicator 1l and of the ship, the ideal condition being obtained when such lag amounts to 90. In practice, the roll angle indicator 11 and the follow-up motor l2 alone will not be able to produce this ideal condition, on account of the retardation or lag caused by the considerable inertia of the weights (trucks and motors) to be propelled. For the purpose of equalizing or counteracting this retardation, the damping device 17 has been provided. As has been explained above in connection with Fig. 2, this damping device, by means of the differential gear 10, transmits to the switch arm 2 a slight additional movement differing in phase by about 90o from the pendulous movements imparted to said arm directly by the follow-up motor l2. These two kinds of pendulous movements will be superposed or combined in the diierential gear l0 in such ar manner that the movements of the switch arm 2 will have a phase lead, relatively to the sine-like deflections of the roll angle indicator 1l, of such extent as to compensate exactly the retardation which the travel of the trucks receives owing to the inertia of the masses to be propelled. The motor l will therefore be reversed before the roll angle indicator ll passes through its Zero position. By this arrangement I secure the desired result, viz.: that the periodic movements of the trucks will lag in phase by about 900, with a close approximation, behind the periodic movements of the ship.

The result obtained by means of the damping device 17 may also be secured by using a gyroscope measuring, or responsive to, the angular velocity of the rolling motion, the deflections of such gyroscope likewise differing in phase by about 90 from the deflections of the roll angle indicator ll. In this case,

however, it would be necessary to superpose these deflections obtained from the reversing pointer in the differential gear 10 upon the control values obtained from the motor l2 in the direction opposite to the one occurring in the case of the control values obtained from the dampingl device 17, because the deflections of the reversing point-er have a phase lead of 90 over those of the roll angle indicator, while the control values obtained from the damping device 17 have a phase lag of about about 900 behind the deflections of the roll angle indicator.

lt is thus by my invention possible to control the stabilizing trucks by the controller connection 2, 3 provided in the armature circuit of their motors in various manners so that in spite of the inertia of their massesv they move periodically substantially with the most favorable phase displacement of 900 in relation to the rolling motions of the ship. By regulating the resistor QQ'connected in the exciter circuit of the individual motors different speeds and travels between the two bogies or trucks, caused by different friction along the track, for instance, may be equalized so that the two bogies move always at the same height. As long as the travels of each bogie towards bot-h sides of the ship arey of equal lenffth, the resistor 23 is short circuited. This case is illustrated in the drawing and exists if the deflections of the ship around her horizontal position are equal towards both sides. If the ship takes up a mean Obliquity, due to list, leakage or the like, the above described control gear in the armature circuit of the motors causes a shifting of the mean position of the bogies t0- wards the lower side of the ship, for instance the port side. By the resulting irregular oscillations which the damping device 30 transmits to the switch disc 33 the contact 34, 36 may be closed, for instance. During that period of the rolling of the ship during which the bogie is located on the left-hand side of the ship the pivoted arm 2 of the controller travels from the position shown in the drawing towards the right and by means of the brush la closes the exciter circuit for the relay so that the short circuiting line 26 is broken by the lifting of the relay armature 25. The series resistor Q3 weakens the motor field so that the bogie is shifted more quickly towards starboard and thus the mean position of the bogie is shifted back again to the c .iter line of the ship. During the following half rolling period in which the bogie travels towards starboard the pivoted switch-arm 2 short circuits the pairs of slide cont-acts 4l, -l, but in this case the circuit is broken at the contact 37 so that the relay Q4 does not attract its armature and the short-circuiting line 26 for the resistor 23 consequently remains closed. When shifting the mean position of the bogies towards starboard there is obtained in a similar manner, by the cooperation of the contacts 34, 37 and al, al, the result that the relay 24 interrupts the short circuit line Q6 for the time onlyk during which the bogie is on the starboard` side of the ship. By the regulation of the motor fields by means of the resistors 22 and 23 synchronism may thus be obtained, on the one hand, between the motions of the individual bogies and, on Athe other hand, each bogie can positively be so controlled that it performs equal movements towards both sides of the ship.

lnsteadof allowing the control members (1l, 17) operated in dependence on the angle of roll to act on the armature current and the control members (30) operated in dependence on the travel of the bogiesto act on'the exciter current of the motor, all the control members may, for instance, be made to act solely upon the armature current of the motor. In case of a plurality of motors or bogies being employed the regulating connection provided in the armature circuit must then be provided separately for each motor.

.It will be readily understood that instead of the devices shown by way of example for the accumulation of the roll angle deflections, I may employ other apparatus, such as hydraulic damping cylinders which are reciprocated from both sides by springs compressed and relaxed in correspondence with the travel of the bogies, this displacement corresponding approximately with the accumulated or resultant value of the travel of the bogies and being transmitted to the control switch 33.

If it is desired to employ the control arrangements described to control the bogies in such a manner that they increase the rolling ofthe ship, it is merely necessary to interchange either the armature terminals or the terminals for the supply of the exciter current. As fully explained in describing the mode of operation, the arrangement is then such that the roll of the ship is increased by the movements of the bogies.

In ships which have a tendency to strong oscillations while rolling, it is necessary to let the bogies follow these oscillations quickly. This may preferably be attained by providing a plurality of damping devices, 'for instance by a second damping device connected in series or tandem with the damping device 17 shown in the drawing for the accumulation or resultant of the amounts transmitted by the damping device 17, which then also acts on the switch arm 2 through a second differential gear.

It is generally advisable to employ a plurality, preferably an even number of bogies of equal mass and construction. These are then distributed over the two sides of the ship in such a manner that they do not disturb the symmetry of the ship.

Their starting and stopping then takes place by switching the electric driving motors on at the moment when the ship is just in its symmetrical position, furthermore in such a uence that the movement of the bogies di ers in phase uniformly by 90 from the rolling of the ship.

As mentioned in the preamble to my specification it is in principle naturally also possible to control masses of water by means of the described control gear, the electric motors then driving pumps or blowers connected f in the communication pipes of oppositely located tanks.

Various modifications may be made without departing from the spirit of my invention or the ambit of the appended claims.

I claim as my invention:

1. Apparatus for controlling ship stabilizing masses, comprising driving means for said stabilizing masses, a regulating member for said driving means, a member the movements of which correspond to the extent of the rolling motion of the ship, for adjusting said regulating member, and a damping device adjustable according to the rolling motion of the ship for effecting an additional adjustment of said regulating member.

2. Apparatus for controlling ship stabilizing masses, comprising electric motors for driving said stabilizing masses, a regulating connection for said motors, including a movable switch, a device the movements of which correspond in extent to the rolling angle of the ship, an operative connection from said device to said switch, including a di'erential gear, and a. damping device adapted to be operated by the said first-mentioned device in accordance with the angle of the rolling motion.

3. Apparatus for controlling stabilizing trucks arranged to travel transversely of a ship, comprising an electric driving motor for each truck, a regulating connection for the armature circuits of said motors, members the movements of which correspond to the oscillations of the ship, for controlling said connection, regulating devices in the field circuits of said motors, and a damping device operatively connected with said regulatin devices and responsive to the travel of said trucks.

4. Apparatus for controlling stabilizing trucks arranged to travel transversely of a ship, comprising a driving motor for each truck, a regulating connection common to the armature circuits of all of said motors, members the movements of which correspond to the oscillations of the ship, for controlling said connection, regulating devices in the field circuits of said motors, and a damping device operatively connected with said regulating devices and responsive to the travel of said trucks.

5. Apparatus for controlling stabilizing trucks for ships, comprising driving motors for each truck, a regulating connection in the armature circuits of said motors, common to all of the trucks and including a movable switch, a controlling member the movements of which correspond to the oscillations of the ship, an operative connection between said controlling member and said switch, said operative connection including a differential gear and a damping device connected therewith, regulating resistances in the field circuit of each motor, relays controlling the connection of said resistances with the said field circuits, an energizing circuit for said relays, said energizing circuit including the said movable switch and switch contacts controlled thereby, another switch likewise included in said energizing circuit, and another damping device, arranged to accumulate the resultant of the travel of the trucks, and operatively connected with the last-mentioned switch.

6. Apparatus for controlling ship stabilizing trucks, comprising electric driving motors for each truck, a regulating connection common to all the truclis, in the armature circuits of said motors and including a movable switch, a controlling member the movemlents of which correspond to the oscillations of the ship, an operative connection between said controlling member and said switch, said operative connection including a differential gear and a damping device connected therewith, regulating resistances in the field circuit of each motor, relays controlling the connection of said resistances with said field circuits, an energizing circuit for said relays, said energizing circuit including the said movable switch and contacts adapted to be engaged by said switch, another switch lil ewise included in said energizing circuit, another damping device, arranged to accumulate the resultant of the travel of the trucks, and operatively connected with the last-mentioned switch, a follow-up motor controlling the lastmentioned damping device, and a teletransmission system comprising a transmitter connected with the said driving motor and a receiver controlling said followup motor.

'Z'. Apparatus for controlling ship stabilizing masses, comprising driving means for said stabilizing masses, control members for regulating said driving means, said control members comprising a damping device which consists of a spiral spring, a shaft to which the inner end of said spring is secured, means for controlling said shaft in accordance with the angle of the ships rolling motion, a housing connected with the outer end of the spring, damping cylinders and pistons operatively connected with said housing, and a shaft likewise connected with said housing and to the outer end of said spring, to transmit the resultant movement.

8. Apparatus for controlling ship stabilizing masses, comprising driving mleans for said stabilizing masses, control members for regulating said driving means, said control members comprising a damping device which consists of two spiral springs coiled in opposite directions, a shaft secured to the inner ends of said springs, means for controlling said shaft in accordance with the ships rolling motion, a housing connected with the outer ends of said springs, damping cylinders and pistons operatively connected with said housing, a pipe connecting said cylinders, an adjustable valve controlling said pipe, and another shaft likewise connected with the outer ends of said springs, to transmit the resultant movement.

9. Apparatus for controlling ship stabilizing masses, comprising driving means for stabilizing mlasses adapted to be transferred periodically transversely of the ship, alternately in opposite directions, a reversible regulating device for said driving means, a controlling member the movements of which are proportional to the oscillations of the ship, an operative connection between said controlling member and said regulating device to eftect an adjustment of the regulating device by the controlling member in phase-synchronism, and means the position of which varies in response to oscillations of the ship, for effecting a phase shifting in the periodic adjustment of said regulating device.

In testimony whereof I alx my signature.

HERMANN HORT.

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