US1993549A - Automatic steering system for dirigible craft - Google Patents

Description

March 5, 1935.

. B. B. HOLMES AUTOMATIC STEERING SYSTEM FOR DIRIGIBLE CRAFT Filed July 14, 1951 5 Sheets-Sheet 1 March 5, 1935. v B. B. HOLMES ,9

. AUTOMATIC STEERING SYSTEM FOR DIRIGIBLE CRAFT Filed July 14, 1931 5 Sheets-Sheet 2 Z'mventor 5% 85 555/2 awsm s2 v (Itfornegs March 5, 1935. B, HOLMES 1,993,549

- AUTOMATIC STEERING SYSTEM FOR'DIRIGIBLE CRAFT Filed Jul 14, 1951 5 Sheets-Sheet s a .6 May 164 S67 SQ? Q8 3nventor Patented Mar. 5, 1935 PATENT OFFICE AUTOMATIC STEERING SYSTEM FOR DIRIGIBLE CRAFT Bradford B. Holmes, Stonington, Conn., assignor to Ruth V. Holmes, Stonington, Conn.

Application July 14, 1931, Serial No. 550,792

47 Claims.

This invention relates to a method of and apparatus for the automatic steering of dirigible craft. It finds particular application-in the steering of small ships or yachts; although it is not limited to such use and no limitations are intended, ex-

cept as the scope of the claims is limited by disclosures of the prior art. It is applicable to the steering of craft provided with either magnetic or gyrocompasses, and is otherwise of general application.

In the automatic steering of dirigible craft in the prior art, for example, ships, it has been customary to swing the rudder through a comparatively large angle as soon as the ship departs from her course; to add smaller increments of rudder as she departs further from her course, then to take oil most of the rudder as soonas the ship starts to return to her course, and finally, to ease her balck under small decrements of rudder; thus making four consecutivecharacteristic movements that the rudder follows for each swing of the ship.

Steering of this character is very complicated and diflicult toobtain automatically because several factors have to be taken care of by the mechanism without manual manipulation. I

First-The mechanism must be so designed as to be capable of increasing or decreasing the throw of the rudder, in case external conditions cause the ship to swing'back on or farther ofi her course, after the rudder has once been swung to -a position corresponding to the initial movement of the craft from her course. These changes in rudder position must be made quickly and the mechanism should be capable of anticipa'ting'the amount of the swings of the ship from her course before such swings are completed.

Second-Adjustable lost-motion mechanism 40 must be provided in the rudder follow-up system in order'to counteract the lost motion in the steering system, so that the movements of the rudder will correspond exactly to the movements of the ship from her course, or tobe more exact, the movements of the compass from the true course. If such mchanism is not provided for, the steering is erratic and varies in accordance with the wear on the parts of the steering mechanism. As the wear increases, the lost motion or backlash increases, and hence the movement of this mechanism tends to increase the discrepancy between the movement of the rudder and the movement of the ship.

Third.,The automatic steering device should be provided with automatic helm centering mechanism, so as to maintain the true amidships po.

sition of the helm as varying external conditions tend to cause the ship to follow, not her true course, but a course displaced from the true course, due to the swings being more on one side than the other of-the true course.

Fourth.-Adjustable sensitivity mechanism must be provided to prevent undue working of the power steering mechanism when the condition of the sea is such that a false yaw or corkscrewing movement is imparted to the ship. With ordinary adjustments the mechanism would be moving the rudder continuously and violently although such movement would have little or no effect upon the movement of the ship along her true course. The devices set forth above involve complicated mechanism, present diflicult problems of installation, and when applied to the steering of yachts require too much especial knowledge or skill on the part of the operator to make their use practical, especially on small yachts. Accordingly, this invention is intended to provide a simple system which is capable of accurate steering, and at the same time, is simple to install and 'comparatively inexpensive. Furthermore, a system embodying this invention does not require any special skill or qualifications on the part of the operator.

The method of steering embodying this invention consists in periodically and at recurrent intervals swinging the rudder from its amidships position for a length of time, or by an angular amount bearing some fixed relation to the position of the craft relative to her course at the time each impulse is initiated. Constantly rotating timing mechanism is provided to cause the rudderto be subjected to these'impulses in accordance with the indications of thecompass on the craft, and in case the craft s on the true course at a time when an impulse to be given to the rudder, therudder position will not be disturbed. The craft is, therefore, steered by subjecting the rudder to impulses so that it acts for a part of the time, and during the remainder of the time trails freely.- 45

Concisely stated, the method consists in giving the rudder a series of periodic swings or impulses whenever the vessel is ofi her course, and allowing it to trail or assume its amidships position in the intervals between swings. The extent of the rudder swings is roughly proportioned to the amount the vessel is off her course. For instance, when the vessel is more than about 5 off her course, as in changing course or in heavy weather, the rudder swings are great enough the vessel is restored to her course by a series of individual steps rather than a swing.

After each impulse the rudder automatically swings back to its amidships position, so that the craft is acted on by a series of impulses which counteract the tendency of the craft to overswing or yaw from its true course. Inasmuch as the extent of rudder movement is varied in accordance with the position of the craft, sudden impulses through which the craft is moved depend upon the position of the craft as indicated by the compass needle at the time the rudder impulses are initiated. It is to be noted that during the swing of the craft off her course, she is acted on by a series of restoring impulses with intervals of trailing rudder between them, and

not by a continuous application of rudder.

It may be assumed, for example, that an impulse isapplied to the rudder once a second. Accordingly, when the craft is V oil its course, 10 of rudder may be applied for of a sec- ,ond each second. i

When 1 /2 oflthe course second each second.

'When 2 off the course second each second. 1

When 4 off the course second each second.

When 6"ofl! the course second each second.

When 10 or more oil the course 1% second each second.

Or the above maybe varied to give a smaller angle of rudder on the small departures, as

When oflf the course 5 rudder for second each second.

When 1%" ofi the course l /2 rudder for fl second each second.

When 2 oif the course 10 ond each second.

When 4 oil the course 10 rudder for 96second each second.

When 6 oi the course 10 rudder for secrudder for sec- ..ond each second.

When'10 or more oil the course,10 rudder for 1 6 second each second.

The figures given above are only illustrative and on large ships the duration of an impulse might be asmuch as 5 to 10 or more seconds, and-the rudder movement from 2 to 5 during this period. It is contemplated that therudder will not make its complete swing during impulses of extremely short duration,.the main object of the method being to apply rudder impulses at periodic intervals when the ship is 01f her course, and to increase the length of such impulses as the ship .moves further from her course, and shorten the impulses as she returns to her course.

In this specification frequent use will be made One definition of this of the termamidship's. term is that condition of a craft wherein the helm is at its central position, and'the 'plane of the rudder coincides with that of the longitudinal axis of the craft. This definition appliesunder ideal operating conditions, but practically,

such conditions are seldom if ever'met.. The

craft is usually subjected to forces from propeller thrust and from wavesand wind. Move ments of the helm to counteract these forces the rudder of the-boat."

give rise to a condition wherein the helm is deflected from its central position and the rudder is deflected from the plane of the longitudinal axis of the craft in order to hold the craft on its course. Thislatter condition is still an amidships condition so long as the craft is on its course, and wherever the term is used it is intended to cover both of the conditions described.

Although, as stated above, this invention is of eneral application, it has been illustrated and described as applied to a ship, and particularly to a small ship or yacht, having a magnetic compass. Several forms of apparatus for carrying out this method have been illustrated, and vari ous modifications indicated, which render the apparatus suitable for application to craft of different sizes.

- The invention will be more fully understood from the following description, when read in connection with the accompanying drawings, in which,--

Fig. 1 is an assembled view of one form of automatic steering apparatus employing pneumatic control, and embodying this invention;

Fig. 2 is a diagrammatic view showing one form of circuit arrangement suitable for use in "the system shown in Fig. 1;

Fig. 3 is a detailed view of a portion of the apparatus shown in Fig. 1, showing the details of the control switch which determines the length of the impulses applied to-the rudder;

. Fig. 4 is an end view of an electro-pneumatic valve, suitable for use in the system shown in Fig. 1, certain of the operating parts being 'indicated in dotted lines;

Fig. 5 is an axial sectional view or the valve,

the section being taken on line 5-5 of Fig. 4; Fig. 6 is a diagrammatic view of a modified form of steering system designed for electromagnetic operation.

Fig. '7 is a detailed view of a modified tiller and quadrant arrangement suitable for use in an electro-pneumatic system such as that illustrate inFig. 1;

Fig. 8 is a diagrammatic'view of a further modified system suitable for use in steering large heavy craft, either pneumatically or hydraulically; v

Fig. 9 is a detailed view of the rudder, tiller and quadrant construction for the system shown in Fig. 1; and

Fig. 10 is a plan view of a. quadrant and tiller arrangement equippedfor hydraulic operation; as on a large ship having a steam steering'engine.

Referring to Figs. 1 and 2 of the drawings, the

system there shown comprises the usual elements of a manual steering system including a compass, a wheel, a rudder, and actuating mechanism connected between the, wheel and the rudder.

The apparatus is so designed that the boat may by the compass for moving the rudder electropneumatically, the compass being provided with an electric contactor :which controls the electric circuit to an electro-pneumatic valve. Air under pressure is supplied to this valve from a suitable source; and directed from this valve to 'a pneumaticcylinder-containing a piston connected to Having described the system generally, the details of the various elements will now be pointed out. In Fig. 1, the reference character 11 represents the body of the compass which is weighted at the bottom in the usual manner. The body 11 is mounted to. oscillate about a geometrical point with the usual gimbals comprising knife-edge trunnions 12 which engage seats provided for them on the gimbal ring 13. The gim-- bal ring 13 is, in turn, carried on knife-edge trunnions 14, engaging seats provided for them in the fixed supporting ring 15. The ring 15 is mounted in conventional manner on a base 16, so asto allow the compass body to move freely abouttwo mutually perpendicular axes, and to maintain its position in a horizontal plane in claimed.

spite of rolling and pitching movements of the ship.

The compass body includes the usual rotatable compass card 17 carrying the compass needles 18, a contact arm magnet 18*, and a rotatable contact arm 19. The magnet 18 and arm 19 are secured together, and one end of the contact arm 19 cooperates with a series of spaced contacts (Fig. 2) carried on a settable head 21, these con-' tacts being. separated by segments of insulation 22. The broad method embodied in this case of moving a contactor into contact with selected contacts of a series according to the changing indications of a movable indicating member, is disclosed and claimed broadly in my Patent No. 1,939,775, granted December 19, 1933, reissued October 9, 1934, No. 19,338. v This method consists in shifting the contactor alternately into positioning engagement with the indicating member, and out of such engagement into contact with one of a series of contacts selected by such positioning. 4

The details of the compass contact system will be described generally, and for the details thereof reference may be had to my copending application Ser. No. 412,418, filed December 7, 1929, in which this mechanism is fully described and For the purposes of this application, it will be sufficient to say that the contact arm 19, together with its magnet 18', is adapted to rotate independently of the compass needle 18, but is magnetically related to it and tends to follow it in its movements whenever it is free. Furthermore, the contact arm 19 is periodically lifted into contact with the settable head 21, by the energization of solenoid 20 mounted concentrically with theaxis of the compass needle and the contactarm. When the solenoid 20 is energized, the arm 19 is brought into firm engagement with one of the contacts of the settable head 21, the parts being so arranged that only one contact can be engaged at one time.

Means are provided for periodically energizing the solenoid 20, so that arm 19 follows the compass needle around, and then is lifted against the contacts at periodically recurrent intervals so that the mechanism controlled by the 'compass receives controlling impulses each time the arm 19 is lifted.

The contacts on the settable head 21 are designated R R and L and L etc. The contacts designated R' correspond to movements of the craft off its course in a starboard direction, and requiring the application of left rudder. Similarly, contacts L correspond to movements off the course in a port direction and requiring the' application of right rudder. This nomenclature will be followed throughout the specification. These contacts are each connected through a wire in cable 23 to a rotating control switch. This switch (see Fig. 3) includes a rotatable contact drum 24 (shown developed in Fig. 2) supported by members 25 carried by base 26. The base 26 also supportsa driving motor 27 which is connected to the drum 24 by a worm and worm gear 28. As here shown, the motor 27 is an electric motor and is adapted to be operated by the source of electricity on the boat and to drive the control drum continuously when the automatic steering mechanism is in use. It is to be understood that any: other suitable driving means may be substituted provided it has substantially constant speed.

The drum 24 carries a plurality of conducting segments T, L, R, O and 32, the segments 32 and 0 being connected together by a wire 33 embedded in the insulation 29, which separates the various segments from one another. Rotatable with and mounted on the same shaft with drum .24 is an oil slinger X to prevent oil from the bearing reaching the contact drum.

Mounted above the contact drum 24 is a contact bar 30 of insulating material carrying a plurality of adjustable contact brushes 31 which engage the face of the drum and contact with either the insulation-29 or the contact segments, depending upon the position of the drum. of the two of these brushes, designated 31 and 31 31 is capable of contacting only with the segment T, while the brush 31 can engage either segment T or 32. The segment T controls the periodic energization of the solenoid 20 for contact arm 19. Once during each revolution of the drum 24,brush 31 engages segment 32 to energize the zero magnets, and positively insures a return of the rudder to its amidships position once during each revolution of the drum.

In other words", at the end of each impulse given to the rudder and when solenoids 20 is deenergized, the zero positioning magnets are energized to positively return the rudder to amidships position before solenoid 20 is energized again to give the rudder another impulse.

The-remaining brushes cooperate with the segments L, R or O; the segment L controlling port movements of the boat,'segment R controlling starboard movements, and segment 0 determining the amidships position of the rudder.

In addition to driving the contact switch, the motor 27 drives an air compressor 34 by suitable means, suchas a belt 35. The function of this compressor-is to supply fluid pressure to an electro-pneumatic valve 36 through a pipe 37. The outlet from compressor 34 has connected to it, in addition to the pipe 37, an auxiliaryg pipe 38 which is extended to and terminates. near the steering wheel and includes a pressure gage 39 and a rel'ef valve 41. The gage 39 enables the operator of the boat to ascertain at all times what the pressure in the system is, and to adjust this pressure by manipulation of the valve 41,'thereby.

discharging air from the system.

The rudder of the boat, designated 42, is carried by the usual rudder post 43, which post is squared at the top to receive a washer 44 having a squared opening in it, and adapted. to act as a base for one end of a quadrant 45 and of a tiller 46. The squared top end 47 of the rudder carries an adapter 48 having a squared opening through it and a cylindrical outer surface. This adapter is rigidly secured tmthe rudder post and in contact with washer 44 bya pin 49. The tiller 46 carries a tubular extension 51 which fits around the outside of adapter 48 and is connected to it, by a key 52 in the adapter, and a slot 53 in the tiller extension. This arrangement allows a slight play between these two parts and assures that the tiller will always return to its zero position between rudder swings. When a single free spring is lised, or two opposed compression springs are used, to center the tiller, there will be a small arc of movement when the springs may not be powerful enough to center the tiller. A slight play of key 52 in slot 53 builds up enough spring pressure before the rudder is moved, to insure a complete return of the rudder under the action of the spring. The same result may be obtained at somewhat more complication, in the case of two opposed springs, by enclosing them in cages.

Secured to the tillermidway between its ends, is a return spring 54 capable of both compression and extension, and having its base end carried,

in a spring saddle 55'secured to the quadrant 45. Spring 54 is capable of free extension when the tiller is moved upwardly, as shown in Fig. 1, and

l is guided and supported during compression movement by the saddle 55. The tiller also has pivotally connected to it, at 56, a piston rod 57, which cooperates with a cylinder 58 carried by quadrant 45 and pivotally mounted thereon.

Piston. rod 5'I 'carries a piston 59, movable within the cylinder 58, one end of this cylinder being connected to the electro-pneumatic valve by a' flexible pipe 61, and the other end by a similar pipe 62. ,Fluid pressure may be supplied to either end of this cylinder to move the piston 59 in one direction or the other, and thereby actuate the tiller 46 and the rudder connected to it. The pivotal mounting of the rod 5'? on the tiller, and

-' of the cylinder 58- on the quadrant, allows such motion to take place freely. The throw of tiller 46 is limited by a stop bar 40 pivoted to the tiller 46 at 50, and carrying adjustable stops 60. These stops limit the movement of bar 40 by engage! ment with an eye 100 on the quadrant. As shown in the drawings, the range of angular movement of the quadrant 45 exceeds that of the tiller 46 relatively thereto, because the tiller movement is ;limitedby stops 60. Consequently, manua1 control can be assumed at any time without effective interferences from the power operated means.

This quadrant 45 carries a'tubular extension 63 (see Fig. 9) which surrounds and moves about the extension 51- as a bearing, and this extension is supported atthe bottom by washer 44. When the boat is to be steered manually, movement of the rudder is brought about by movement of quadrant 45 which in turn actuates the tiller 46 through spring 54.

The manual steering mechanism comprises a' vrope or'cable 65, the two ends of'which are carried around the rudder post in the u'sual'manner, and contact with gd'ooves'64 in the quadrant. The rope is guided in pulleys 66 to an actuating drum 6'7; rotatable withshaft 68 by wheel 69. when the boat is being steered automatically, the friction of the rope in its bearings is sufllcient to prevent the quadrant from rotating, hence the extension 51 of tiller 46 may move within extension 63 of the quadrant without turnin the steering wheel or moving the parts carried between it and the rudder post. If conditions are contact arm 19 of the compass causes actuation of an'electro-pneumatic valve 36 to control the admission of compressed air to the cylinder 58. The valve 36 comprises a hollow valve housing 72, the front end of which is closed by an interiorly flanged cover plate '73 secured to the housing as by screws '74. Mounted within the housing 72 is a magnet ring '75 having three pairs of electromagnets which are spaced around the ring at 60 intervals (Fig. 2). Two of these magnets, designated 76, determine the zero or amidships position of the rudder, and those designated '7'? and H determine the right and left positions, respectively, of the rudder.

Rotatably mounted inside the field ring '75 is an armature 78 carried by a shaft '79. This armature has two arcuate extensions 80 immagnetic relation to the various electromagnets within the housing. One end of shaft 79 rests in a bearing 32 secured in an extension 81 of housing '72, while the other end projects through the cover, plate 73 and rests in a similar bearing 82 within an extension 83 of cover plate 73. Movement of the armature 78 through an angle of more than 60 is prevented by an arm 85 having an integral collar 84 secured to the shaft 79.

operates with flxed stops 86 and 87 on the inner face of cover plate '73.

Accordingly, when the magnets 76 are energized, the armature 78 occupies its neutral position shown in Fig. 2. When the magnets 77 are energized, the armature assumes a position in which the arm 85 engages stop 86, and when magnets W are energized, this arm engages stop The portion of shaft '19 inside of cover plate This arm 85' 00-- 73 carries a gear 88 rigidly secured to it by a flanged extension 89 within the chamber 90.

Communicating with the chamber 90 and extend- 7 'and 93 which are threaded to receive suitable such that this friction will not prevent move-v ments of-the manual control, an arm 70 secured to shaft 68 may be locked to the base 1 6 of the compass by a pin 71, thereby positively preventing actuation of the manual steering mechanism by the automatic means;

, During automatic steering, movement. of the.

hose nipples for the flexible pipes 61 and 62.

Movably mounted within the bore 91 is a.valve piston 94 having enlarged heads 96 and 97 movmg in air-tight relation to the walls of the bore.

This piston is shown as occupying its neutral position, and it may be moved either to. the right or to the left by rotation of gear 88 cooperating with a rack on the bottom of the piston. From thisdescription it will be clear that when magnets '16 are energized, all the parts will-occupy the positions shown in Figs. 4 and 5. The fluid pressure inlet v is thereby connected to both the outlet ports 92 and 93, while the fluid pressure from bore 91 is prevented by piston heads 96 and 9'1. Consequently, the piston 59 will occupy its neutral position in the cylinder 58 because equal pressure will be exerted on both sides of it. Under these conditions,- the rudder'is controlled solely-by the spring 54 and the drag of the rudder through the water.

The inside of the valve is underfull air pressure, hence packing'glands on shaft79 are un-:

necessary. The valve is completely balanced against the fluid pressurej'at all times and will operate at any pressure because the undercut portion 91" of the. bore 91 prevents pressure from being exerted upon the piston. 94 from one side escape of 1 only as it passes the ports 92 and 93 during its operation.

When magnets 77 are energized, the armature 78 is rotated until the arm 85 strikes the stop 86, moving valve piston 94 to the left, connectingport 93 to atmosphere through the bore 91, and connecting port 92 with the inlet opening 110 through chamber 90. Under these conditions, fluid pressure is supplied through the pipe61 to move the rudder 42 to its right or starboard-position. When magnets 77 are energized, the armature 78 is rotated, moving arm 85 against stop 87 and moving piston 94 to the right ,so as to connect port 92 to atmosphere, and connect port 93 to the air chamber 90. With the parts in this position, air pressure'is supplied to the cylinder 58 through pipe 62 so as to move the rudder 42 to its left hand or port position. It will be clear that Whenever fluid pressure is supplied to the cylinder 58 through one of the pipes 61 or 62, the valve piston 94 will always assume such a position that the other side of the piston will be connected to atmosphere through the bore 91, thereby allowing the piston 59 to move freely in the cylinder to the position corresponding to the actuation of the electromagnetic means.

Having described the structural elements of the system, reference will now be had to Fig. 2 of the drawings, wherein the operating circuits of the system are shown diagrammatically. In this figure reference character 98 designates a source of current which is employed to actuate the motor 27, and also to supply the energy for the electro-pneumatic valve. Although the source is here indicated as a battery, it is obvious that it may be an electric generator driven from the propeller shaft or engine 'in'case of small boats, or

\ it may be the generator which supplies the electric lighting plant on large boats. Likewise the compressor 34 has been shown as driven by an electric motor 27, but it is obvious that it also may be driven by the motor of the electric lighting plant on largeboats, or by the engine connected to the propeller shaft in small boats. The

compressed air may also be supplied to the sys-- tem from an air storage tank.

A double pole switch 99, placed near the steer-. ing wheel, serves to start the motor and energize the control mechanism.

When the switch occupies the closed position, as shown, and the drum 24 is in such a position that the segment T connects 'the brushes 31 and 31* together, the solenoid 20 is energized, thereby lifting contact arm 19 into engagement with one of the associated contacts. The circuit for solenoid 20 is from the positive terminal of source 98, through switch 99, wires 101 and 102, solenoid 20, wire 112, brush 31 segment T, brush 31 and wires 103 and 104, back through switch 99 to the negative terminal of the source. I

When the boatis proceeding on her course so that contact arm 19 occupies the zero or neutral position as shown, and the circuit for solenoid 20, just traced, is closed, the magnets '76 are energized so as to hold valve piston 94 in its neutral position, and the two sides of piston 59 and cylinder 58 are connected together and subjected to equal pressure to hold the rudder in its neutral or amidships position under the action of spring 54 and trailing action ofthe rudder through the water. Under such conditions, the circuit for the magnets 76 is as follows: From the positive terminal of source 98, through switch 99, wires 101 and 105, windings of magnets '76, wire 107, brush 81 connected to the zero contact of settable head 21, the zero contact of the head 21, contact arm 19, wire 112, brush 31 to the contact segment T, and thence backzto the negative terminal of .brushes 31 and 31 by movement of segment T.

When brushes 31 and 31' strikethe insulated portion between the ends of segment T, the solenoid 20 is deenergized to drop the arm 19 and disconnect it from the zero contact. The sole noid 20 is periodically energized and deenergized by the rotation of contact segment T, and the circuit for magnets 76 is likewise closed periodically each time the circuit for solenoid 20 is closed, so long as the boat stays on her course. Each time that brushes 31 and 31 rideoffthe segment T onto the insulation of the drum 24 so as to break the circuit of solenoid 20, deenergizing it and dropping the contact arm 19, all of the circuits for the electro-pneumatic valve are opened, because the contact arm 19 drops away from the contacts on head 21.

Itis essential, in steering according to methods embodying this invention, that the rudder return to its amidships position each time after it has swung to one side or the other, and it is for this reason that segment 32 is provided on the drum 24. This segment cooperates only with brush 31 connected to the negative side of source 98. Consequently, soon after the brushes 31 and 31 leave the segment T to deenergize solenoid 20, brush 31 strikes segment 32 and completes a circuit for the neutral magnets 76, independently of the contacts on the compass head 21.

This circuit is from the positive terminal of source 98, through switch .99, wires 101 and 105, magnets 76, wire 107, brush 31 connectedtothe I zero contact of settable head 21, segment 0, wire tralposition and enablingthe spring 54 to center .t-he rudder.

When the boat moves off her course in a; starboard direction, and the control switch moves so as to energize the solenoid 20 and to lift the contact arm 19, this arm engages one of the contacts R R R, R or 11, in accordance with the angle through which the boat swingsfrom her course. If the extent of the movement is such that the contact arm engages contact R the circuit for the magnets 77 will be closed for a substantial period, because contact R -is connected to segment R near theend of drum 24 and the circuit of the magnet 77 will be closed during the interval when brush 31, connected to contact R engages the segment R.

The circuit for magnets 77 may be traced from the positive terminal of source 98, through switch 99, wires 101 and 105, magnets 77 wire 108, extreme right hand brush 31, segment R,

brush 31 connected to contact R contact R contact arm 19, wire 112, brush 31 segment T, brush 31', wires 1 03 and 104, and switch 99,.back to the negative terminal of the source.

When this circuit is closed, the armature 78 is moved so that its axis alines with the axis of eleetromagnets 77*. Arm 85 engages stop 87 and piston 94 occupies its right hand position which the port 92.is connected to atmosphere and the port 93 connects chamber 90 with the cylin der 58 through pipe 62, thereby moving the rudder downwardly or to its port position. This circuit remains closed until the drum 24 rotates far enough so that brush 31 rides onto the insulation between segment R and segment 0. While brush 31 is in contact with the insulation 29, solenoid 20 still remains energized through segment T which is still under the brushes 31 and 31 Contact arm 19 therefore is held against the contact 1?. and when the brush 31 rides onto segment 0, the circuit just traced, will be interrupted by brush 31 striking insulation 29, and the following circuit through the magnets 76 closed. This circuit is from the positive terminal of source 98, through switch 99, wires 101 and 105, magnets 76, wire 107, middle brush 31, seg-. ment 0, brush 31 of contact R", contact R contact arm' 19, wire 112, and brush '31, to segment T; and thence through brush 31 and wires 103 and 104 to the negative terminal of the source.

change in circuit, caused by movement of brush 31 onto segment 0, will move the armature 78 from its position in line with magnet 77 'to a position in line with magnets 76, so as to return the rudder to'its neutral position. After a short interval the solenoid 20 will be deenergized to disengage contact arm 19 from contact R thereby interrupting this circuit at, the same time that the circuit for solenoid 20 is interrupted. II for any reason the interval in which the magnets 76 are energized is very short, or if the rudder does not return to its amidships position,

the engagement of brush 31 with segment- 32 will energize magnets 76 again and complete the movement of the rudder to such position.

. The operation just described is such as to tend to return the boat to her course, but if one rudder swing from contact R is insuillcient for such restoration, subsequent swings through contacts R R3 and B may take place and ease the boat back to her course. When the contact arm engages the zero contact on head 21, the rudder is not moved from its amidships position, because energization of the electro-pneumaticvalve maintains valve piston 94 in its neutral position. li-the boat swings of! her course on the port side so that the compassneedle indicates a subunder such conditions is as follows: Positive terminal of source 98, switch 99, wires 101 and 105, magnets 77 wire 106, left hand brush 31,

segment, L, brush 31' of contact L contact L contact arm 19, wire 112, brush 31F, segment T, brush .31, wires 103 and 104, and switch 99 to the negative terminal of source 98.

This circuit is closed ior a short interval and when brush 31 strikes the insulation 29 between ts L and 0, magnets 77'- are deenergized and brush engages segment 0 to enersize, the magnets 76 and move the electropneumatic valve to neutral position, thus restor-' ing therudder to its neutral or amidships position. After ashort interval the brushes 31 and 31" leave the segment '1, thereby deenergizk .solenoid m and allowing contact arm 19 to realineitseltwlthtbenoedle. Further posed centrally of and secured thereon.

the characteristics of the particular vessel, and

will operate satisfactorily on an air pressure of approximately pounds per square inch or more,

depending on the size of cylinder 58. The only adjustment necessary is to vary the amplitude of the rudder swing by adjusting stops 60 orto alter the air pressure. )Thfi system offers the advantage that manual control may be assumed at any time without deranging or shutting off the automatic mechanism. Assumption of manual control merely disturbs the set course which the craft is following, without deranging the automatic mechanism. This mechanism, accordingly, continues to try to direct the craft back to the set course, but it is, of course, affected by the disturbed amidships position of the rudder resulting from movement of the steering quadrant under the action of the manual means. As soon as manual control ceases, the automatic means. becomes effective to return the craft to the set course. The manual means must, of course, be returned to its amidships position to enable the automatic mechanism to steer a proper course. Furthermore, the complete system is small and compact and may be installed on yachts having various kinds of standard equipment with simple modifications. This feature is disclosed and claimed in my copending application, Ser. No. 585,122, flied January 6, 1932.

The apparatus just described is well suited for largeyachts ,in which considerable power is required to move'the rudder from one position to another, particularly in rough water. In smaller yachts in which less power is requiredto move the rudder, the system may be considerably, simplified by replacing the rudder controlling '46 as before and the quadrant 45 is rotatably mounted around the sleeve on thetiller as previously described. The quadrant is, however, modified by the addition of a member 113 dis- The member 113 comprises two upstanding cage members having spring sockets 114 and 114 to receive springs 115, one on either side of the tiller 46, and engaging sockets'120 in the tiller. In-

asmuch as member 113 is secured to the quadrant, the action of springs 115 is such as to centralize the tiller whenthe quadrant is in fixed,

The sacks117 engage plungers 113 and 118 on the tiller 46, and movement of the tiller in either direction is limited by adjustable stop screws 119 and-119" carried by the member 113 and preferably integrally formed with the pockets.

118" and 118 It will be clear that 'under normal conditions when air is supplied to both of the sacks 1l7 atthesamepressure,andthe sacksareconnected together, the tiller will occupy its central posirant and connected to the segments of the con- I tion, as shown, and when both of the sacks are subjected to atmospheric pressure the springs 115 will likewise hold the tiller in .the neutral position. If, however, air pressure is supplied through pipe 62 to the associated sack 117, while the other sack is vented to atmosphere through the electro-pneumatic valve, the inflated sack will expand and force the tiller 46 to the right until it engages the stop screw 119.

In similar manner, the tiller may be moved in the opposite direction by venting pipe 62 to atmosphere and supplying fluid pressure to the other sack 117 through pipe 61. This arrangement provides a very simple mechanism which can be installed readily, and will operate smoothly and noiselessly to move the rudder from one position to another as the electro-pneumatic valve is controlled from the compass and-the control switch, and is adapted for use with very low air pressure. It will be understood' that the arrangement of Fig. 7. is adapted for use in' the system shown in Fig. 1, .and that it merely replaces the parts carried by the quadrant 45, the quadrant being capable of control manually in the manner previously described.

The steering of small yachts can also be accomplished according to the methods embodying this invention without the use of pneumatic or hydraulic actuating means for the rudder. In such installations, it has been found that a purely electromagnetic means will furnish the necessary power for actuating the rudder, and one embodiment of means of this character is shown in Fig. 6.

Referring to Fig. 6, the parts there shown are similar to those in Figs. 1 and 2, with the exception that the pneumatic mechanism is entirely removed and the tiller actuatingmechanism carried by the quadrant is altered, so that the control switch actuated by motor 27 operates directly to control operating magnets carried by the quadrant, and cooperating with an armature carried bythe tiller. In this figure, the tiller designated 121 is provided with a transverse head 122 of magnetic material and having spaced pole pieces 124 and 124*. This head, together with its pole pieces, is secured to the tiller 121 by suitable means, such as a nut 123. Movement of the tiller, together with the head, is limited by stops on the lateral arms of quadrant 45. These stops comprises rods 125 having heads 128. The rods are carried in bosses 127 on the quadrant arms, and serve as supports for centering springs 126. Each of the springs engages the tiller 121 at one end and a boss 127 at the other.

Mounted on the arcuate portion of the quadtrol drum 24 are a plurality of electromagnets disposed along an arc coinciding with the path of movement of pole pieces 124 and 124", and in spaced relation thereto. The electromagnets are designated by the same reference characters as the corresponding segments on drum 24 to which they are connected. 4

The circuits, with the exception of those of the electromagnets carried by the quadrant, are similar to those of the system shown in Figs. 1 and 2, hence a brief description of them will be suflicient.

The six magnets are arranged in symmetrically disposed pairs. eration of the rudder for counteracting movements of the boat toport, and magnets R, R for counteracting movement to starboard. In sim- Magnets L, L control o'pilar manner magnets O, O'serve to hold the der in its amidships position.

A single source of current 161 furnishes energy for operating the magnets and all of the magnets have a common return wire 129. Energization of the circuits is controlled by a switch 99.

If the boat swings off her course to starboard thereby bringing contact arm 19 against one of the R contacts, for example, R the R magnets are energized to throw the rudder to port. The circuit for magnets R is from -the positive terminal of source 161, over common return wire 129, windings of magnets R, wire 167, to extreme brush 31, segment R, brush 31 connected to contact R contact R arm 19, wire 163,switch 99, and wire 109 to the .negative terminal of the source. This circuit is only closed when solenoid 20 is energized to thereby hold arm 19 against the contact R. v

The circuit for solenoid 20 is from source 161, overwire 168, brush 31 segment T, brush 31, wire 162, solenoid 20, wire 163, switch 99, and wire 109, back to the source.

rud-

Should the boat swing off her course on the When the boat is on its course, the magnets O are energized periodically, the rudder being held in its amidships position in the meantime by centering springs 126 and the trailing of the rudder through the water. is from source 161, over common wire 129, windings of magnets 0, wire 164, zero contact of head 21, contact arm 19, wire 163, switch 99, and wire 109, back to the source.

When the operation of the compass is such 'as to energize the, magnets O, the tiller is held in its neutral position, as shown, because these magnets attract the pole pieces 124 and 124" equally. When magnets L are energized, the tiller is moved to the left, or to a position in which the armatures are in front of the magnets L, thereby moving the rudder to its starboard position. When'the magnets L are deenergized, the rudder is moved to its central position by springs 126, and when segment 32 on drum 24 connects with brush 31 ,the magnets 0 will, be energized to assist in returning the rudder to-its central position. It will be understood that magnets O are energized when contact arm 19 engages the zero contact on head 21 and the associated brush 31' engages segment 0. Likewise when'segments R. are energized, the armatures are attracted to positions in front of these magnets, thereby moving the rudder to its port position, the parts being restored to neutral position when magnets R are deenergized to allow springs 126 to act, the movement being quick. and positive .when magnets O are energize'd. The pole pieces 124 and '124 are of considerable arcuate extent, to insure actuation of the rudder from one position to another, even though the pole pieces be displaced from the magnets which are energized.

The steering systems above described have been indicated as applicable to the steering of The circuit for magnets O ends of the bore 91 being connected to the inlet of the oil pump.

An hydraulicarrangement of this character suitable for use on large ships provided with steam steering engines, is shown in Fig. 10. Referring now to this figure, the reference character 245. designates the quadrant connected to the rudder post 248, in a manner similar to that shown in Fig. 9. Rotatably mounted within the "extension of this quadrant is an extension on tiller 246, the tiller being secured to the rudder post by a key 252. As here shown, the quadrant together with the parts carried thereby, is adapted to be actuated when the ship is being steered manually by a steam steering engine comprising two steam cylinders 247 having pis-' ton rods 249 connected to' cranks 250. These cranks are mounted so as to actuate a worm 251 which in turn meshes with the worm gear 253 carried on a shaft 254, carrying a spur gear 255. The spur gear meshes with the toothed portion'256 of quadrant 245.

Accordingly, the quadrant may be moved one direction or the other, depending upon which of the steering cylinders'247 is supplied with steam, the control of the steam tothese cylin-" ders being exercised in any suitable and well known manner. When automatic steering mechanism embodying this invention is to be applied to ships having steering apparatus of the general character disclosed, the quadrant "245 is equipped with a what hydraulic cyl-' inders 257 and 257, to which hydraulic fluid may be supplied through inlet pipes 258 and 258. Each cylinder contains a. piston connected to piston rods 259 and 259, the outer ends of which rods are pivotally secured to tiller 246 at 260. Accordingly, when hydraulic fluid is supplied to .cylinder 257, the tiller is moved upwardly, and when such fluid is supplied to cylinder 257, the tiller is moved downwardly, it being understood that when fluid is supplied to one cylinder, the other is arranged so that the fluid therein is allowed to escape.

As previously described, in steering according to the method embodying this invention, it is desirable to have some means for returning the rudder to amidships position at the end of each impulse supplied to it. 'Therefore,.in this instance, it is preferred to employ a pair of centering springs 261 and 261, mounted on the lateral arms of quadrant 245 and held in position by a spring stop bar 262. The tension of these centering springs may be individually ad justed by the'cooperation .of nuts 267 engaging combination guidesand spring saddles 265. The free ends of stop bars 262 carry spring stops 264 against which the springs abut on one side,

while the other side engages the tiller.

' they hold the tiller and the It will be readily'understood that when the two hydraulic cylinders 257 and 257- are subjected to equal pressure,'or to no pressure at all other than thatof atmosphere, the springs 261 and 261'- may be so adjusted as to tension, that parts actuated thereby in the central or amid-ships position.

As pointed out hereinbefore, this system is so designed that manual control may be taken over at any time and will function independently of the automatic control.

The system shown in Fig. 1, with the modifications described, can be adapted to the steering of larger vessels, but because of the sluggishness of the movement of such vessels, it is essential to proper steering that more rudder be supplied in stopping the swing of the vessel oil? the course than in returning her to the course. Accordingly, it is preferred to add the relay mechanism shown diagrammatically in Fig. 8, so as to apply more rudder as the ship is leaving her course than is applied when she is returning to it.

Referringnow to Fig. 8, the compass controlling mechanism there shown is similar in all its details to that already described. The control switch is likewise similar, with the exception that the relation of the left and right hand segments L and R is reversed from that shown in Fig. 1 in order to simplify the connections In this system there is provided a set of electromagnets mounted in a magnet ring 138. Inside of this ring, and rotatable with respect thereto, is an armature 131' having pole pieces 130 which move in magnetic relation to the electromagnets on ring 138. Armaturel31 is rotatable on a shaft and carries with it a contactv arm 132, movable about the shaft but frictionally held against the armature by a spring washer 133 and a nut 134. Arm 132.carries a contact 135 adapted, when moved counterclockwise, for engagement with an adjustable stationary contact 136, but thearm is limited in its clockwise movement by an adjustable stationary stop 137. Hence, the arm 132 moves with 'its armature but is limited in its move ment to the distance between contact 136 and stop 137. 1

Each of the contacts on the compass head 21, with the exception of contacts L and R, is connected to a pair of relay magnets oppositely disposed inside of ring 138. For example,.contact R is connected 'to two diametrically related electromagnets 81. The parts are so designed that when the two diametrically related electromagnets are energized, the axis ofarmature 131 assumes a position in axial alinement with the energized magnets. If the zero mag-. nets corresponding to the zero position of contact arm 19 are energized/the armature assumes the position shown in the drawings.

The contacts.135 and 136 control a pair of relay magnets 143 cooperating with an armature 144 on relay bar 141 rotatably mounted in stationary bearings 142. Rotation oi. bar 141 in one direction is brought about by energization' of magnets 143, thereby moving the armature 144 into contact with the magnets. Rotation in the other direction, when the magnetsv 143 are deenergized, is caused by spring 147,- the movement of armature 144 being limited by a stop screw 146 in stationary abutment 145. The circuit for relay magnets 143 isfrom the positive terminal of source 158, through switch 159, wire 157, contacts 136. and 135, windings of magnets- The relay bar 141 carries a series. of spaced stationary contacts 139 which are connected consecutively to the electromagnets in the lower half of the ring'138. Contacts 139 are-adapted, when movedupwardly by energization of magnets 143, to engage stationary contacts 148, and when moved to their other position by spring 147 to engage contacts 149.

The circuit for solenoid 20 is similar to that of Fig. 1 and is similarly controlled. It is from the positive terminal of source- 158, through switch 159, wire 153, solenoid 20, wire. 152, brush,

31 segment T, brush 31*, wire 154, and switch 159, back to the source.

v The contacts148 adjacent the right hand end of bar 141 connect to brushes 31 designated E, F, G, H, I, corresponding to long intervals of rudder movement, while the remaining contacts 148, with the exception of the middle contact of brush A, are connected to brushes 31 designated B, C, D, E, F, corresponding to shorter rudder movements. In similar manner the contacts 149 at the left end of relay bar 141 are connected to brushes designated E, F, G, H, I, while those, .at the right are connected to contacts B, C, D, E, F. The middle one of contacts 149 is connected to brush A. The object of this arrangement is to cause the rudder to be held in its deflected position for a substantial period during movements of the ship ofi her course, so that the rudder is applied for long intervals when the ship is moving off her course,

but for shorter intervals as she returns to her course, this action corresponding to the so-called meeting and easing system of manual steering.

The extreme brushes K and K associated with drum 24 areconnected to contacts L and R respectively, of head 21 and do not pass through any of the magnets of ring 138. The reason for this arrangement is that under extreme move ments of the ship when rudder is applied for long intervals, it is not necessary to produce any easing action until the ship approaches her course.

One form of hydraulic valve 151 suitable "for use in a system of-this type, is shown diagrammatically as having four electric contacts, one

1 being common to all the actuating magnets in the valve, and the other three, L, 0, and R, being connected to brushes K, A and K, respectively. The method of operation of this valve is similar to electropneumatic valve 36, hence no detailed description need be given. Y

The operation of the' mechanism shown in Fig. 8 is generally similar to that which has already been described in connection with Figs. 1 and 2, with the exception'that whenever the ship changes her course either one way or the other, the relay is brought into operation. If,

for example, theship swings to port through a distance sufiicient to bring arm 19 against contact L and energize magnets P, the arm 132 will rotate with armature 131 until contact 135 a series of substantial periods to counteract the swing of the ship from her course. The circuit for magnets P under these conditions, is from the positive, terminal of source 158, through switch 159, wire 153, contact arm 19, contact L ,v

windings of P?, contacts 139 andllfi energize magnet P the movement of armature Y 131 will be sufiicient to disengage contacts 135 and 136, thereby deenergizing relay coils 143 and allowing spring 147 to move the relay bar 141 to its bottom position. In this position contact 139 connected to magnets P will engage contact B resulting in the rudder being swung to starboard for a series of comparatively short intervals so as to tend to ease the ship back on her course. If the ship subsequently swings ofi her course again in the same direction as she returned from the prior swing, so that contact R is energized, the relay being deenergized, contact E will be energized causinga series of impulses of substantial duration. If the ship swings in the opposite direction from which she returned from the prior swing, the direction of rotation of armature 141 will be reversed, the relay thrown to the energized swing of the ship off her course in either direction starts a series of rudder impulses of considerable duration. After the swing has been checked and the ship starts to return to her course, a series of rudder impulses of substantially less duration is started. This action takes place regardless of whether the swing of the ship be to starboard or port, and whether it be large or small.

It will be understood that the above operation takes place at periodically recurrent intervals, and that the position of the hydraulic valve 151 is determined by the position of the contact arm 19 associated with the compass needle. Rotation of the drum 24 causes periodic energizationof the solenoid 20, and movement of the rudder to either starboard or port for a period depending upon which brush 31 associated with control drum 24 is energized. The above mechanism is not necessary on small craft'that respond quickly to the rudder, but desirable on large ships or heavily loadedships which are sluggish in their rudder response.

From the foregoing description, it will be noted that if relatively low air pressure and heavy centering springs are used, the' extent of rudder throw as well as the time of its duration will increase as the craft departs farther from her course, as there is not time enough for the air operating under this condition to move the rudder to the stop against the combined water and spring resistance. If-relatively light springs and heavy .air pressure are used the rudder can be completely thrown during each period.

.With an intermediate condition of moderate spring and air pressure, the extent as well as duration of the rudder swing will increase with combination of fixed spring and manually variable air pressure form a very simple and efl'ective rudder control.

- though the modifications of the above invention and the method of applying the various emcation in the steering and control of dirigible craft of all kinds and it is not desired that the claims be limited in scope other than is necessitated by the prior art.

What is claimed is:

1. A method of steering dirigible craft having a rudder, which consists in subjecting the rudder to successive deflections at predetermined recurrent intervals, and timing the duration of the deflections according to the angle through which the craft has deviated from its course at the time of the deflection.

2. That method of steering dirigible craft having a rudder, which consists in swinging the rudder from its amidships position at predetermined fixed recurrent intervals, andvarying the duration of the swings according to the amount of angular deviation of the craft from its course at the time of the swing. I

3. The method of steering dirigible craft ha ing a rudder, which consists in periodically swinging the rudder from its substantially amidships position by a substantially constant amount,

turning the rudder to a position tendingto hold the craft on its course after each swing.

, 5. The method of steering dirigible craft having a rudder, which consists in swinging the rudder from and returning .it to a substantially amidships. position at periodically recurrent intervals whenever the craft is oil its course, and varying the duration of each swing according to the angular position of the craft relative to its course at the time the swing is initiated.

6. The method of steering dirigible craft having a rudder, which consists in swinging the rudder at predetermined intervals from its substantially amidships position a varying amount in accordance with the angular deviation of the craft from its course at the time the swing is initiated, and-returning the rudder to a substantially amidships'position ai'ter each swing.

7. The method of steering dirigible craft having a rudder, which consists in swinging the rudder at predetermined intervals from its substantially amidships position, varying the duration and extent of each swing in accordance with the angular deviation of the craft from itscourse at the time the swing is initiated, and returning the rudder to a substantially amidships position I der from and returning it to a substantially amidships position at periodically recurrent intervals whenever the craft is of! its course, and varying the extent and duration of each swinggccording to the angular position of the craft relative to its course at the time the swing is initiated.

10. A steering system for dirigible craft having a rudder, comprising rudder actuating means; compass controlled means for periodically energizing the rudder actuating means; and automatic means for controlling the length of the periods during which the rudder. actuating means is energized.

11. An automatic steering system for dirigible craft having a rudder, comprising rudder actuating mechanism; a compass; and automatic timing means controlled by said compass for rendering said rudder actuating mechanism active for periods varying with the position of the craft relative to its course.

12. An automatic steering system for dirigible craft having a rudder, comprising a compass; electric contact mechanism on said compass; periodically operated means for controllingsaid mechanism in accordance with the position of the craft; rudder actuating mechanism; and means connected to the contact mechanism on the compass for controlling said rudder actuating mechanism, said last-mentioned means including mechanism for varying the length of the periods in which said rudder actuating mecha nism is active.

13. An automatic steering system for dirigible craft having a rudder, comprising a compass; electric contact mechanism onsaid compass; periodically operated means for controlling said mechanism in accordance with the position of the craft; rudder actuating mechanism; and means connected to the contact mechanism. on the compass for controlling said rudder-actuating mechanism, said last-mentioned means including mechanism for varying the extent of rudder throw.

14. An automatic steering system for dirigible craft having a rudder, comprising a compass;

electric contact mechanism on said compass; periodically operated means for controlling said mechanism in accordance with the position of the craft; rudder actuating mechanism; and means connected to the contact mechanism on the compass for controlling said rudder actuating mechanism, said last-mentioned means including 4 mechanism for varying the length of the periods in which said rudder actuating mechanism is active, and the extent. of rudder throw.

15. An automatic steering system for dirigible 4 craft havingv a rudder, comprising a compass;

electro-pneumatic means for actuating the rudder; and automatic rotating reading transmitting mechanism electrically connected with said compass for controlling said electro-pneumatic means in accordance with the indications of the compass.

16. An automaticsteering system for dirigible craft having a rudder, comprising a compass; electro-pneumatic means for actuating the rudder; meanson said compass for controlling said electro-pneumatic means in accordance with the indications of the compass; automatic means for varying the length of the periods in which the rudder actuating means is active; and means on said compass for rendering the rudder -act1 i-, ating means active or inactive in accordance with the position of the craft relative to its course.

17. An automatic steering system for dirigible craft having a rudder, comprising a. compass; fluid pressure means for actuating said rudder; a source of fluid pressure; and a rotating'reading transmitting mechanism electrically connected 25 the. craft relative to its course.

with the compass for controlling the supp y or fluid pressure to said fluid pressure means, in accordance with the compass indications.

18. An automatic steering system for dirigible craft having a rudder, comprising a. compass; fluid pressure means for actuating said rudder; a source of fluid pressure; means for controlling the supply of fluid pressure to said fluid pressure means, in accordance withthe compass indications; and automatic means for varying the length of the active periods of said fluid pressure means.

19. An automatic steering system for dirigible craft comprising a rudder; electromagnetic means for actuating said rudder; a compass; electric contact means on said compass; and electric timingmeans for controlling the energize.- tion of said electromagnetic means in accordance with the compass indications.

20. An automatic steering system for dirigible craft comprising a rudder; electromagnetic means for actuating said rudder; a compass; and electric contact means controlled by the compass for energizing said electromagnetic means for periods varying in length with the position of 21. An automatic steering system. for dirigible crai't comprising a rudder; means for actuating said rudder; a compass; compass controlledmeans for controlling the rudder actuating means; means for timing the length of the active periods of said rudder actuating means; andmeans interposed between said timing means and said compass for causing said rudder actuating means to be active for longer periods when the compass indicates that the craft is departing from its course than when it indicates that the craft is returning to its course.

22. An automatic steering. system for dirigible craft comprising a rudder; means for actuating said rudder; a compass; compass controlled means for controlling the rudder actuating means; means for timing the length of the active periods of said rudder actuating means; and means interposed between said timing means and said compass for causing said rudder actuating means to be active for longer periods and to throw the rud-' der a greater amount when the compass indicates that the craft is departing from its course than when it, indicates that the craft is returning to its course. V s

23. An automatic steering system for dirigible craft, comprising a rudder; a tiller; 8. member pivotally connected to said rudder and adapted to be controlled by the ships steering wheel; a

compass; fluid pressure means for actuating said rudder relative to said manually controlled mem' ber; a source of fluid pressure; and means for controlling the supply of fluid pressure to. said fluid pressure means in accordance with the com-; pass indications.

' 24. An automatic steering system for dirigible craft comprising a rudder; a tiller operatively connected to said rudder; manually operable means for actuating said rudder; and fluid pressure operated means interposed between said tiller and said manually operable means, said manually operable means being capable of swingingsaid rudder whether said fluid pressure operated means is activeor inactive.

25. An automatic steering system for-dirigible craft comprising a rudder; a tiller operatively connected to said rudder; a quadrant operatively connected to 'said rudder; vmanually operable means ior actuatingsaid quadrant; and fluid pressure operated means interposed between said tiller and quadrant. Y

26. An automatic steering system for dirigible craft comprising a rudder; a tiller operatively connected to said e'udder; manually operable means for actuating said rudder; fluid pressure operated means interposed between said tiller and said manually operable means; and resilient means for centering said tiller when said fluid pressure operated means is inactive.

2'7. An automatic steering system for dirigible craft comprising a rudder a tiller operatively connected to said rudder; manually operable means including a quadrant for actuating the rudder; automatic means carried on said quadrant for actuating said tiller; and resilient means for centering said tiller with respect to said quadrant.

28. An automatic steering system for dirigible craft comprising a rudde a tilier operatively connected to said rudder; manually operable means for actuating said rudder, said means including a quadrant operatively connected to the tiller and electromagnetic operating means carried by said quadrant and interposed between said tiller and said manually operable means.

i 29. An automatic steering system for dirigibleto periodic swings in a corrective direction whenever the craft is oii its course, the duration of such swings being controlled according to the turning movement of the craft in such manner that the swings are of longer duration when the craft 'is turning from its course, than when it is turning toward its course.

31. A method of steering dirigible crafthaving a rudder, which consists in subjecting the rudder to periodic swings in a corrective direction whenever the cratt is of! its course, the extent of such swings being controlled according to the turning movement of the craft in such manner that the swings are of greater extent when the craft is turning from its course, than when it is turning toward its course. i

32. A method or steering dirigible craft having a rudder, which consists in subjecting the rudder to periodic swings in a corrective direction when.- ever the craft is ofi its course, the duration and extent or such swings being controlled accordin to the turning movement or the craft in such manner that the swings are of greater duration and extent when the craft is turning from its course, than when it is turning toward its course.

erable means for moving said quadrant and tiller in concert.

34. An automatic steering craft comprising a Hidden 0. tiller operatively connected to said rudder; a quadrant operatively connected to said rudder; manually operable means for actuating said quadrant;'and powersystem for dirigible operated means interposed between said tiller and quadrant. p

35. In automaticsteering apparatus for dirigible craft, a rudder including a rudder post; a tiller connected to said post; a quadrant hinged to said tiller; manually operable steering means connected to said quadrant; and automatic steering means reacting between said tiller and said quadrant.

36. The method of steering dirigible craft along a set course which consists in imparting to the rudder a plurality of series of swings when the craft is off its course, each of the swings of a series being of equal amplitude but those of sue-- cessive series being of progressively larger amplitude as the craft is departing from its course and of progressivelysmaller amplitude as the craft is approaching its course.

37. An automatic steering system for dirigible craft comprising a rudder; a tiller operatively connected to said rudder; manually operable means for actuating said rudder; and power means interposed 'between said tiller and said manually operable means, said manually operable means being capable of swinging 'said rudder whether said power operated means is active or inactive.

38. An automatic steering system for dirigible craft comprising .a rudder; a tiller operatively connected to said rudder; manually operable means for actuating said rudder; power operated means interposed between said tiller'and said manually operable means; and resilient means for centering said tiller when said power operated means is inactive.

39. Automatic steering mechanism for dirigible craft comprising a rudder; a control member for moving the rudder; a manually operable member mounted adjacent and for cooperation with said control member to. steer said craft;

.and power operated means operatively connecting said control member and said manually operable member for controlling movement of said control member relatively to said manually operable member.

40. An automatic steering system for dirigible craft, having a rudder and comprising a quadrant and manual means for operating it; a member capable of pivotal movement with respect to the quadrant and operatively connected to the rudder; and power operated means interposed between said quadrant and member.

41. An automatic steering system for dirigible crait, having a rudder and comprising a quadrant and manual'means for operating it; a pivoted member carried by the quadrant and operatively connected to the rudder; and power operated means connected to said quadrant and tosaid member for moving said member relatively to said quadrant.

42. An automatic steering system for dirigible craft, comprising a rudder; means for actuating the rudder; a compass; compass controlled means for timing the length of the active periods of said rudder actuating means; and means for varying the length of the active periods of said rudder actuating means in accordance with thedirection of movement of the craft with respect to its set course. a

43. An automatic steering system for dirigible craft, comprising a rudder; means for actuating the rudder; a compass; compass controlled means for timing the length of the active periods of said rudder actuating means; and means responsive to a change in direction of turning of the craft for varying the length of the active periods of the rudder actuating means.

44. An automatic steering system for dirigible craft, comprising a rudder; rudder actuating mechanism; a timing means for rendering the rudderactuating mechanism active for certain periods of time; a'compass; compass controlled means for rendering said timing means responsive to changes in heading of the craft; and automatic means responsive to changes in direction of movement of the craft relative to its course for varying the length of the periods during which the rudder actuating mechanism is active.v

45. In an automatic steering system for dirigible craft, a rudder; rudder actuating mechanism; a controller for said mechanism; compass controlled means for varying the response of said mechanism to said controller; and automatic switching means responsive to turning of the craft be selectively connected with the controller contacts to render the controller responsive to changes in heading of the craft; and automatic switching means for connecting certain of ,the contacts when the craft is departing from its course, and certain others of the contacts when the craft is moving toward its course.

4.7. In an automatic steering system for dirigible craft, a rudder; electrical rudder actuating means; a controller including a plurality of electric contacts for causing operation of the rudder actuating means; compass controlled means for rendering said controller responsive to changes in the heading of the craft, said compass controlled meansincluding a plurality of electric contacts; and automatic switching means responsive toturning of the craft for selectively connecting 'certainof the controller'contacts to certain oi. the compass controlled contacts to vary the rudder action in accordance with the direction of movement of the craft toward or away from its set course.

BRADFORD B. HOLMES.

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