US2131951A - Automatic steering device for ships - Google Patents

Description

Oct. 4, 1938. F. s. HODGMAN AUTOMATIC STEERING DEVICE FOR SHIPS Original Filed Sept. 19, 1934 4 Sheets-Sheet l mm J9EE". mot: 2%

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AUTOMATIC STEERING DEVICE FOR SHIPS Original Filed Sept. 19. 1934 4 Shets-Sheet 3 Hi5 ATTORNEY.

Oct. 4, 1938. F. s. HODGMAN AUTOMATIC STEERING DEVICE FOR SHIPS Original Filed Sept. 19, 1934 4 Sheets-Sheet 4 a. I I

Patented Oct. 4, 1938 UNITED STATES PATENT OFFICE AUTOMATIC STEERING DEVICE FOR SHIPS Application September 19, 1934, Serial No. 744,628 Renewed February 25, 1938 9 Claims.

This invention relates to improvements in automatic steering devices for ships, wherein the main course controller is automatically maintained synchronous with the gyro compass and wherein a predetermined course change may be ordered and set on the course indicator dial and the ship will automatically come around to the new course without further manipulation by the pilot. It is understood, of course, that I use the word ships" throughout the specification in the generic sense and intend to include thereby both water borne and air borne vehicles, that is, both vessels and dirigible aircraft. A further object of the invention is to improve the controller arrangement so that more sensitive control is obtained. A further object of the invention is to provide a means for limiting at will the amount of rudder throw regardless of the total amount of course change desired. In other words, if a group of vessels is steaming in formation, it may be desired to change course through any desired angle, such as but for the individual ships to swing around an arc of predetermined radius in doing so. With the ordinary automatic steering device the rudder would be run hard over in order to make such a large course change and the ship would turn to the new course about a short radius arc. I have provided, according to my invention, means so that the rudder may be limited to any desired angle in making a turn through the automatic steering device.

Referring to the drawings,

Fig. 1 is a diagrammatic view, in perspective, of the elements of my improved automatic steering device.

Fig. 2 is a diagrammatic view, in skeleton form, of the same.

Fig. 3 is a vertical section through the top portion of the steering stand.

Fig. 4 is a plan view of the indicator dial on the stand.

Fig. 5 is a detail sectional plan view of the contact on the master controller, the section being taken on line 55 of Fig. 3.

Fig. 6 is a sectional view through the auxiliary controller, and Fig. 7 is a wiring diagram of a slightly modified form.

This invention is an improvement, in many respects, on the type of automatic steering system shown in my prior Patent No. 2,015,183, dated September 24, 1935, for Self-synchronous automatic pilots, and in my prior Patent No. 1,965,378 of July 3, 1934, for Sensitive remote control system and automatic pilot, and to that extent is a continuation of the same.

Referring first to the Figs. 1, 2 and 3, my automatic steering device is shown as controlled from a gyro or other compass (not shown) through a repeater motor 35, the transmitter for which is geared to rotate many times for one turn of the ship. Said motor operates an auxiliary controller 36, shown in the form of trolleys which contact with reversing contact rings 31 and 31'. Said contacts control a small reversible motor 21 which operates the main controller contacts l5. As shown in Fig. 2, the motor 21 drives a gear 28 on shaft 39'. One end of said shaft is shown as having a pinion 29 which turns a large gear 30, furnishing a follow-back connection to the controller 36. This gear is shown as having a large hub 3| (Fig. 6) on which is keyed a sleeve 4|] having annular teeth 4|, by means of which said sleeve may be axially moved along said hub, by means of a pinion 43 on shaft 44 which meshes with said teeth 4|. By turning said shaft, the sleeve may be moved along said hub for the telemotor lost motion adjustment. To this end the sleeve is provided with a triangular slot 45, into which projects a pin 46 on an interior sleeve 41. Said sleeve has secured thereto a contact carriage 48 which supports the reversing contacts 31, 31'. It will readily be seen that by adjusting the sleeve 40 axially, the amount of lost motion between the pin 46 and the walls of the slot 45 may be adjusted to vary the telemotor adjustment. The trolleys 20' and 20" are carried by a central shaft 2| actuated by repeater motor 35, either directly as in Fig. 2 or indirectly as in Figs. 3 and 6, through gears 33 and 33. Slip rings 23, spring arm 80, and brushes 23 and 23" are shown on the outer surface of carriage 48 for leading current out of the split rings 31 and 31'.

A hand lever 24 mounted on shaft 24 controls a clutch which couples and uncouples shafts 39 and 39, and hence the servo motor 21, from the main contacts I5. When said handle is in the position marked gyro, clutch faces 25, 26 are closed and the motor 21 turns said contacts through shafts 39 and 39', differential 20, worm i9, worm wheel l8 and shaft 38, the clutch being held closed by the spring 22. When, however, the handle is thrown to the hand position, the clutch is open and all mechanical control from the gyro compass is disconnected. At this time the compass side of the differential 20 may be prevented from rotating by a plurality of pins 50 on spring housing 22' which engage pin 5| on clutch 26 (see Figs. 2 and 3).

The master controller in this instance is shown as contact arm 55 and opposite contacts 56, 51, which arm is operated from a cam device on shaft 38 (Figs. 3 and 5) having camming surfaces l6. Secured to sleeve 8 adjacent said cam device is a member 53 on which is pivotally mounted a rocker arm 54 having rollers I8, I8 thereon adapted to be engaged by one or the other of the cam surfaces on said cams 16. In the position shown in Fig. 5, the spring arm 55 secured to said rocker arm lies midway between contacts 56 and 51 on member 53, but a very slight movement of the cam in one direction or the other will close one or the other of said contacts, not only because of the shape of the cam but because the contact arm 55 is much longer than the radius of cam I6 or the radius of rocker arm 54. By this means, coupled with the auxiliary motor control, very quick action of the main steering engine is secured with very slight lost motion.

The follow-up from the steering control motor I to the controller may be of any suitable type, mechanical or electrical. As shown in Fig. 2, suitable gearing 3, 4 and 5 is provided for this purpose, which may also serve to actually turn the rudder or rudder control from the main steering wheel |'I' (Fig. 1) or from the wheel I'I (Fig. 2), which in this figure performs either the function of the gyro-pilot trick wheel or the main pilot wheel by pushing it back or forward to engage either clutch face 5 on sleeve I on which bevel gear 5' is mounted, or clutch face 6 on shaft I| connected by sprocket I8 to large sprocket II on differential 28. Sleeve I is shown as turning a worm wheel 4| through worm I4 and gears 8. Worm wheel 4| is secured to a sleeve 8 which carries the member 53 of contactor l5. Shaft 38 extends through said sleeve and may carry at the top thereof 'an indicator 68 showing the course which has been set with respect to the compass points, which may be marked on the card 6|. Said card is shown as secured to a large gear 62 which is frictionally mounted on the hub of the worm wheel 63, friction contact being provided by spring 64. Said card will therefore normally rotate with said worm wheel, but may be set with respect thereto by pushing in on the handle 65, thus bringing the crown gear 66 into mesh with said gear 62. The worm wheel 63 is shown as actuated from a worm 61 on the shaft 68 of a sprocket 69. The chain 69 coupled with said sprocket is shown as leading both to the sprocket I8 on the shaft II of the course changing wheel l1 and also to a sprocket connected to the planetary arm of a differential 28. The card 6| therefore, when read in connection with the index 68 which is shown in the shape of a ships hull, will show continuously the ship's compass heading as long as automatic steering is used, even including the short time that the course is being changed, at which time it may be used for setting in the desired course change, since the scale on card 6| may be read not only on the index 68 but also on the fixed lubbers line I2.

When steering by hand (i. e., through trick wheel I'I), index member 68 will show wheel position. To this end, the index member 68 also has an index I6 at the rear representing wheel position, and sleeve 8 may also have an indicator secured thereto in the form of a graduated segmental card I5, having a zero index 11'. By comparing I6 and II the rudder follow-up may be observed and by reading I6 on scale 11 the amount of turn of the wheel is indicated. A mask I8 is cut out adjacent said scale indices to show the index I6 at the rear end of the index 88. Scale 11 and index 11' may also be read with reference to the lubbers mark I8 on mask I8 to show rudder position.

In order to limit the rudder throw for the purpose above described, I show in Fig. 1 an on and-off rudder control handle. 88, shown as mounted on a shaft 8| which is both rotatably and slidably mounted. When said shaft is in the forward position under the influence of the spring 82, the contacts 83 and 84 are bridged and contacts 85 and open. In this position the circuit to the master gyro pilot controller I5 is open and the contacts beneath the handle 88 are energized. Therefore, when the handle 88 is rotated to the right, for instance, the contacts 81, 81 are bridged and the power motor I actuated to drive the rudder in the proper direction. Opposite movement of the handle will have the reverse operation by closing contacts 89, 88'. When, however, the handle 88 is pushed to the rear, the contacts 85 and 86 are bridged, thus placing the master controller contacts in the control of the power motor.

In using this portion of my invention, let us suppose that the ship is being steered automatically and the pilot desires to change course in other words, to steer due east instead of due north, as indicated in Fig. 1. The pilot first rotates the trick wheel II until 90 registers with the lubbers mark I2. Simultaneously the ship's index 68 will turn counterclockwise 90 and the rudder will start to move to starboard. The rudder will continue to move to starboard, unless interrupted, until it reaches its hard over position, but if the pilot desires to turn at a given rate, he pulls out the handle 88 when the rudder indicator 'II registers the desired angle, say 15, on the index I8. This will interrupt the circuit to the power motor. When the ship has about reached the course, the pilot may again push in the handle 88 or he may turn the handle 88, before pushing in, to steady the ship on its course by hand, and only push the handle in after the ship has been brought to the new course, as indicated by the ship's pointer 68 registering with the 90 mark on the compass dial 6|.

In steering by hand (with the lever 24 in the hand position), the card 6| no longer represents the compass course which has been set and the index I6 may then be used as a wheel position index, cooperating with the rudder index 11' to show whether the rudder is following the wheel.

Referring now to Fig. '7, there is here illustrated a wiring diagram showing a slightly modified form of the invention in which the cam contactor I6 is replaced by an escapement form of contactor and in which an electric follow-back means is employed from the rudder instead of mechanical shafts. The auxiliary motor 21 and contactor 36 may be the same as shown in the other figures. The preferred construction of contactor is to have the angular position of rings 31 and 31 slightly displaced. By this means, together with a special winding on the motor 21, a very quick stoppage of the motor armature is secured, as follows:

The motor 21 is shown as provided with a continuously excited field winding 98 and the armature is connected directly across the collector brushes 23, 23" which bear on collector rings 23 (not shown in Fig. 7) With the trolleys and contacts in the position shown in Fig. 7, the current will tend to flow from the plus side of the line through trolley 28", brush 23", armature 75 21 from right to left, and one side R of mid tapped or Wheatstone bridge type resistances R, R to the minus side of the line. However, current would also tend to flow from the plus side of the line through trolley 20', brush 23, through the armature 21 from left to right, and through equal resistance R to the minus side of the line. Therefore no line current would flow through the armature. However, it should be observed there is a direct short circuit through the armature and resistances R, R, and also from the armature through brush 23", trolley 20", trolley 20', brush 23' and back to the other side of the armature. Therefore the armature will be very quickly brought to rest by dynamic braking. In fact, with the small motor employed for driving this contactor, the armature has been brought to rest from a speed of several thousand revolutions within one revolution of the armature. By this arrangement, also, the eifective dead space may be adjusted by varying the relative angular position of the two rings 31, 31'. The application of this special motor circuit to broader fields than electric steering gear for ships is reserved for my continuation application Serial No. 132,713, filed March 24, 1937, for Positional control motors.

The motor 21 operates the contactor as before. In this instance the contactor is shown as comprising a disc l6 carrying a single tooth 9| which normally engages a single notch in a rocker arm 92, pivoted at 93 and thus constituting a Geneva movement. Said arm carries a pair of spring contacts 9!, 94 adapted to contact with fixed contacts 56, 51' upon a slight revolution of the tooth 9| in one direction or the other. Further revolution of the disc I6 in the same direction merely holds the contacts closed until the disc I6 is brought back to its original position or until the large disc 53', on which the pivot 93 is mounted, is revolved in the same direction to restore the original relative positions of the tooth 9| and rocker arm 92.

Disc I6 is shown as mounted on a shaft 38, corresponding to the shaft 38 in Figs. 2 and 3, which is shown as carrying a. ship's heading indicator or reference mark 60' at the top thereof, corresponding to the ship's heading indicator 60 in Fig. 4. A compass card 6| is also shown, as in Figs. 2 and 3. A follow-up worm wheel 4| is shown as operated indirectly from a self-synchronous repeater motor 96, operated from a selfsynchronous sending generator 91 at the rudder. Said motor, being of small power, is shown as turning the gear 4| by means of an electrical power multiplying or follow-up system comprising a contactor 9B which may be similar to contactor 36, which controls the follow-up motor 21, similar to the motor 21. Motor 21' is shown as turning worm wheel ll on the shaft of which is disc 53. The Geneva contactor shown in Fig. 7 has the advantage that it is self-synchronous throughout 360, and through it large course changes may be performed without destroying the synchronism between the compass and the controller.

In accordance with the provisions of the patent statutes, I have herein described the principle and operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combination and relations described, some of these may be altered and others omitted without interfering with the more general results outlined, and the invention extends to such use.

Having described my invention, what I claim and desire to secure by Letters Patent is:

1. In an automatic electric steering gear for ships, a compass governed follow-up controller, means for setting in any desired change in course, a non-follow-up or off and on controller, and a switch on the latter and operable thereby for transferring the rudder control motor from the former to the latter controller for limiting the rudder throw.

2. In an automatic steering gear for ships, an electric controller comprising a rotatable cam member, a pair of contacts one or the other of which is adapted to be closed by slight movement of the cam in either direction, a rotatable member supporting said contacts, a motor actuated by said contacts, compass controlled means for turning one of said members, and follow up means from said motor for turning the other of said members.

3. In an automatic steering gear for ships, a compass actuated controller, a small power motor actuated therefrom, a rotatable cam member, a pair of contacts one or the other of which is adapted to be closed by slight movement of the cam in either direction, a rotatable member supporting said contacts, and rudder follow-up means for turning one of said members, the other member being differentially turned from said motor.

4. In an automatic steering gear for ships, a compass actuated controller, a small power motor actuated therefrom, a cam member, a pivoted contact arm, one part of which is adapted to be moved by said cam, the other part being further from the pivot than said cam and adapted to carry a contact, the cam being so shaped that slight movement thereof closes said contact and further movement leaves it unchanged, said motor operating to turn said member.

5. In an automatic steering gear, a compass actuated controller, comprising two pairs of semicircular rings each spaced from the other, a. relatively rotatable contact for each pair, the two pairs being slightly displaced with respect to their contacts, and a reversible motor controlled from said contacts, having a continuously excited field and the armature connected across said contacts whereby the armature is dynamically braked when said contacts lie on opposing contacts of each pair.

6. In an electrical steering gear for ships, 3. motor having field and armature windings the former of which is of the continuously excited type, resistances of the Wheatstone bridge type across the armature and to one side of the supply, a steering controller device adapted to send current from the other side of said supply through said armature in one or the other direction and through one or the other half of said resistance, said controller in its mid or standstill position completing a short circuit around said armature to brake the motor dynamically.

7. In an automatic electric steering gear for ships, a rudder motor, a compass governed controller for said motor, and means for effecting a change of course, including a manually operable electric controller for said motor of the push button hard-over type and switching means on said controller for transferring the rudder control from said compass governed controller to said manual controller, the length of time said manual controller is hard-over serving to determine the degree of rudder throw, whereby the rate or turn of the ship to the new course may be limited to any desired rate.

8. In a steering gear for ships, a differential gear train, a steering wheel connected to one arm of said differential, a servo motor for turning the rudder, and a controller for said servo motor actuated from another arm of said diflerential and comprising a rocker arm and a cam-like device turning said rocker arm one way or the other for small relative displacement of said device, acting to drive said servo motor one way or the other until said device returns said arm to neutral, said servo motor having a follow back connection to the third arm of said differential.

9. In a steering gear for ships, a controller comprising a rotatable cam member, a three-position rocker arm which is thrown to one or the other of its outer positions by lesser movement of the cam in either direction, a rotatable member supporting said rocker arm, a servo motor actuated by said controller, steering control means for turning one of said members, and follow-up means from said servo motor for turning the other of said members.

FREDERICK S. HODGMAN.

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