US3147730A

US3147730A - Differential rudder control system

Info

Publication number: US3147730A
Application number: US270265A
Authority: US
Inventors: Franz R Specht
Original assignee: NAUTEC CORP
Current assignee: NAUTEC CORP
Priority date: 1963-04-03
Filing date: 1963-04-03
Publication date: 1964-09-08
Anticipated expiration: 1981-09-08

Description

Sept. 8, 1964 F. R. SPECHT DIFFERENTIAL RUDDER CONTROL SYSTEM 3 Sheets-Sheet 1 Filed April 3, 1965 u B R r w M 6 i w Qw A 1 P Q A p\ p W.

Sept. 8, 1964 3,147,730

F. R. SPECHT DIFFERENTIAL RUDDER CONTROL SYSTEM Filed April 5, 1963 3 Sheets-Sheet 2 FPANZ A. SPEC/47' Sept. 8, 1964 F. R. SPECHT 3,147,730

DIFFERENTIAL RUDDER CONTROL SYSTEM Filed April 3, 1963 3 Sheets-Sheet 5 IN VENTOR.

3,147,730 DIFFERENTIAL RUDDER CONTROL SYSTEM Franz R. Specht, North Miami Beach, Fla., assignor to Nautec Corporation, New York, N.Y., a corporation of New York Filed Apr. 3, 1963, Ser. No. 270,265 3 Claims. (Cl. 114163) This invention relates to steering controls for marine craft and more particularly to a control system for twin rudder boats and the like.

It is an object of the invention to provide a differential rudder control arrangement having particular adaptability to twin screw, twin rudder boats whereby turns are effected by the inboard rudder while the outboard rudder remains substantially in alignment with the propeller wash.

Other objects of the invention are to provide steering means on a boat which permits shorter turning radius, substantially reduces digging in of the bow in turns, substantially reduces tripping action of the rudders, and increases the effect of outboard propeller thrust in making power turns.

An additional object of the invention is to provide a rudder control system requiring a minimum amount of force to articulate the same.

Briefly one embodiment of the present invention, as adapted for a twin screw, twin rudder boat having a rudder arm on each rudder extending normally in a generally forward direction, includes a steering crank member disposed between the rudder arms having a pair of crank arms thereon each normally disposed toward a respective one of said rudder arms at an angle of from about 10 to about 45 relative to said rudder arms. The crank arms are about 25% shorter than the rudder arms and are each interconnected with its respective rudder arm by a mechanical linkage such as a connecting rod or the like. An actuating arm is included on said steering crank member below the plane of the crank arms which is interconnected by suitable linkage means with the helm for actuating the rudder mechanism to effect directional control of the boat.

With such an arrangement as described above each rudder can be swung through a rather wide angle in an inboard turn and only through a relatively small angle in an outboard turn.

Other objects and features of the invention will be apparent in the following specification and claims and in the drawings in which:

FIG. 1 is an isometric view of one embodiment of the invention;

FIG. 2 is a reduced plan view of the apparatus shown in FIG. 1;

FIG. 3 is a section taken along lines 3--3 of FIG. 2;

FIG. 4 is a simplified schematic diagram of an arrangement according to the invention;

FIG. 5 is a simplified schematic diagram of another arrangement according to the invention;

FIG. 6 is a schematic diagram of a modified form of the invention; and

FIG. 7 is another simplified schematic diagram of another arrangement according to the present invention.

Referring now to the drawings, and in particular FIGS. l-3, one embodiment of the differential control system of the present invention is shown and designated generally by reference numeral 10. It is comprised of steering crank member 11 comprising bracket 12 having a base plate 13 which is mounted amidships on a transverse bulkhead 14 disposed adjacent transom 15 of a boat designated generally by reference numeral 16. Extending in a forward direction from base plate 13 are upper and lower arms 17, 18 having respective mounting hubs 19,

United States Patent I 3,147,730 Patented Sept. 8, 1964 "Ice 20 at their outer ends disposed in vertical axial alignment. Said

hubs

19, 20 carry

respective bushing members

21, 22 in which is journaled shaft member 23. Mounted on shaft 23 between

hubs

19, 20 and adjacent hub 19 is bifurcated crank member 24 having

arms

25, 26 extending in respective angular outboard directions. Also mounted on shaft 23 between crank member 24 and hub 20 is actuating arm 27.

Steering crank member 24 and actuating arm 27 are fixed to shaft 23 by suitable means including pinch bolts 28 and are directly connected to shaft 23 by longitudinal key 29.

Boat 16 has twin

rudders

30, 31 having

conventional mountings

32, 33 including forwardly extending

rudder arms

34, 35. Crank

arms

25, 26 on steering crank member 24 are substantially of equal length to

rudder arms

34, 35 and are disposed at respective acute angles, e.g. about 10 to about 45, relative to said

rudder arms

34, 35. Outer ends 36, 37 of

crank arms

25, 26 are interconnected with

outer ends

38, 39 of

rudder arms

34, 35 by connecting

rods

40, 41 and actuating arm 27 is interconnected with pitman arm 42, disposed adjacent one side of the hull and forward of rudder arm mounting means 33, by connecting rod 43. Pitman 42 is further connected with the forward steering mechanism (not shown) of the craft by suitable linkage means such as gear box 44 and rotary shaft 44a. Pitman arm 42 is disposed generally parallel to the actuating arm 27 in order to transmit turning force to the actuating arm 27 at an approximate angle of 90. However, actuating arm 27 need not have any specific angular relationship with respect to pitman arm 42. All that is required is that the crank member 24 with its actuating arm 27 be actuated up to about 45 in both clockwise and counterclockwise directions.

Rotary movement e.g. counterclockwise (as viewed in FIG. 2) of rotary shaft 44a correspondingly turns pitman arm 42 counterclockwise about its pivot 45 and through connecting rod 43 transmits corresponding angular movement to actuating arm 27, thereby pivoting crank arm 25 and through connecting rod 40 pivoting rudder arm 34 in a counterclockwise direction to move rudder 30 counterclockwise as viewed in FIG. 2 representing the starboard turn of the heat When moving in a forward direction. Simultaneously through crank arm 26, connecting rod 41, and rudder arm 35, rudder 31 is pivoted in a counterclockwise direction. However, in view of the angular disposition of

crank arms

25, 26 relative to rudder arms 34, 35 (see FIGS. 4 and 5) inboard rudder 31 is pivoted in a relatively wide angle, e.g. 40, whereas outboard rudder 30 is pivoted only a relatively small amount, e.g. about 11. If

crank arms

25, 26 are about 25 shorter than rudder arms 34, 35 (see FIG. 5) then outboard rudder 30 would turn only about 2 or 3 when inboard rudder 31 is turned about 40 (see dotted lines). It is to be understood that, due to the geometry of the rudder control system described above, when making a turn to port with the craft moving in a forward direction, rudder 30 becomes the inboard rudder and rudder 31 the outboard rudder and relative movements of the two are reversed in a similar fashion.

In a modification of the invention shown in FIG. 6

rudders

30 and 31 are installed at about an angle of 15 from the vertical with their lower portions 46, 47 extending angularly outwardly. In this installation ball joints (not shown) are added to the rudder mounting means 32, 33, which would be apparent to the man skilled in the art, in order to make the actuation of the rudders feasible. With this added feature the turning radius of the craft is shortened even more than with the differential control system described above by controlling the toe of the rudders.

By shortening the connecting

rods

40, 41 as shown in FIG. 7 the rudders can be toed in or out and the running attitude of the boat can be altered, the rudders then acting partially as elevators. With the inclusion of variable

length connecting rods

40, 41 the attitude of the craft can be altered while under way. The variable linkage can either be mechanical or hydraulic with the control placed at the helm.

In the above arrangement steering power is always placed on the crank arms and not the rudder arms. The interconnection between the helm and steering crank member can be by any known means such as mechanical, hydraulic or push-pull cable. Due to the fact that essentially only one rudder is utilized in turning, less force is required to actuate the mechanism thereby placing less strain on the steering gear from the steering wheel to the actuating arm at the steering crank member. This permits the use of push-pull cable in the steering mechanism Which otherwise might not be adequate.

v The various parts of the above mechanism may be made of the usual materials of choice for marine equipment of this type. The rudder arms may be disposed in normally forward directions as shown in the disclosed embodiment or may be used in other modified arrangements, e.g., disposed normally rearwardly or in other preselected directions as desired so long as the advantageous selective actuation of the rudders can be achieved.

It is thus seen that the present invention provides a differential rudder control system particularly adapted to twin screw, twin rudder boats which achieves all of the aforementioned objects.

It is to be understood that changes and additions may be made by those skilled in the art without departing from the scope and spirit of the invention.

What is claimed is:

1. In a twin screw twin rudder boat a diiferential rudder actuating mechanism for articulating the inboard rudder in a turn while maintaining the outboard rudder in substantially neutral position comprising a rudder arm on each rudder extending normally in a forward direction, a steering crank member disposed between said rudder arms and having a pair of crank arms each normally disposed toward a respective one of said rudder arms at an angle of from about 10 to about degrees relative to said rudder arms, said crank arms being about 25 shorter than said rudder arms, linkage means interconnecting each crank arm with its respective rudder arm, and means on said steering crank member for interconnection with the steering means of said boat.

2. In a twin screw twin rudder boat a diiierential rudder actuating mechanism for articulating the inboard rudder in a turn while maintaining the outboard rudder in substantially neutral position comprising a pair of rudders mounted on the hull of said boat at an angle of about 15 from the vertical, a rudder arm on each rudder extending normally in a forward direction, a steering crank member disposed between said rudder arms and having a pair of crank arms each normally disposed to ward a respective one of said rudder arms at an angle of from about 10 to about 45 degrees relative to said rudder arms, said crank arms being about 25% shorter than said rudder arms, linkage means interconnecting each crank arm with its respective rudder arm, and means on said steering crank member for interconnection with the steering means of said boat.

3. In a twin screw twin rudder boat a diiferential rudder actuating mechanism'for articulating the inboard rudder in a turn while maintaining the outboard rudder in substantially neutral position comprising a rudder arm on each rudder extending normally in a forward direction, a steering crank member disposed between said rudder arms and having a pair of crank arms each normally disposed toward a respective one of said rudder arms at an angle of from about 10 to about 45 degrees relative to said rudder arms, said crank arms being about 25% shorter than said rudder arms, connector arms interconnecting the end of each crank arm with the end of its respective rudder arm, and means on said steering crank member for interconnection with the steering means of said boat.

References Cited in the file of this patent UNITED STATES PATENTS 1,717,286 Ward 2 June 11, 1929 FOREIGN PATENTS 277,022 Great Britain Nov. 3, 1927

Claims

1. IN A TWIN SCREW TWIN RUDDER BOAT A DIFFERENTIAL RUDDER ACTUATING MECHANISM FOR ARTICULATING THE INBOARD RUDDER IN A TURN WHILE MAINTAINING THE OUTBOARD RUDDER IN SUBSTANTIALLY NEUTRAL POSITION COMPRISING A RUDDER ARM ON EACH RUDDER EXTENDING NORMALLY IN A FORWARD DIRECTION, A STEERING CRANK MEMBER DISPOSED BETWEEN SAID RUDDER ARMS AND HAVING A PAIR OF CRANK ARMS EACH NORMALLY DISPOSED TOWARD A RESPECTIVE ONE OF SAID RUDDER ARMS AT AN ANGLE OF FROM ABOUT 10 TO ABOUT 45 DEGREES RELATIVE TO SAID RUDDER ARMS, SAID CRANK ARMS BEING ABOUT 25% SHORTER THAN SAID RUDDER ARMS, LINKAGE MEANS INTERCONNECTING EACH CRANK ARM WITH ITS RESPECTIVE RUDDER ARM, AND MEANS ON SAID STEERING CRANK MEMBER FOR INTERCONNECTION WITH THE STEERING MEANS OF SAID BOAT.