US2746677A - Logs for marine vessels - Google Patents

Description

May 22, 1956 D. c. STONE 277459577 LOGS FOR MARINE VESSELS Filed April 28, 1955 w 3-W unnuunnnn 1| IIHIIIIITIIHIIHlTM IO T- MILES TENTHS 'd muz QSW INVEN TOR.

United States Patent LOGS FOR MARINE VESSELS Donald C. Stone, Essex Fells, N. J. Application April 28, 1955, Serial No. 504,482 1 Claim. (Cl. 235-61) This invention relates to recording logs for marine vessels, and specifically to compensated logs operated within the vessel from the drive mechanism or from directly associated equipment.

In off-shore navigation it is desirable to have a means of determining the distance travelled from some known point, as well as the direction in which the vessel has gone. The compass is a common enough device for providing the latter information, but recording logs for letting one know the distance gone are somewhat less plentiful. This is due to the fact that the simpler type, or taflrail log, is inconvenient, and the Pitot tube type is quite elaborate, expensive, and subject to malfunction due to fouling of the openings in the Pitot tube. There has been some use made of counters that tote up the total propeller revolutions, and these may be calibrated to record in knots directly. However the number of revolutions per knot travelled varies substantially with the speed at which the boat travels, and these counters are therefore subject to considerable inaccuracies, especially when a distance has been travelled at different speeds.

It is an object of this invention to provide a means whereby total propeller revolutions may be registered directly as knots travelled, regardless of engine or propeller speed.

It is also an object of this invention to provide an automatic means of compensating for propeller slip in devices whose purpose it is to record distances travelled in boats as a function of propeller revolutions.

These and other objects will become apparent from the following specifications and the accompanying drawing.

In the drawing is shown a housing 1 through which runs a rotatable main drive shaft 2. On the rotatable main drive shaft 2 and within the housing 1 is aflixed a drive gear 3 and also a fly-ball governor 4. Slidable upon drive shaft 2 and subject to action by governor 4 is a cam 5 whose diameter decreases from top to bottom. Within the shaft-borne confines of the governor 4 is a compression spring 6 in position around the drive shaft 2.

Fastened over the lower end of main drive shaft 2 is an end-play limiting collar 7. Extending through a portion of the housing 1, and adjacent to and also parallel to the main drive shaft 2 is an auxiliary rotatable hollow drive shaft 3. Affixed upon the auxiliary shaft 3 and outside of the housing 1 is an end-play limiting collar 9, and affixed upon the auxiliary shaft 8 and within the housing 1 to mesh with the gear 3 is a corresponding driven gear 1% The hollow auxiliary shaft 3 is also provided with a lateral slot 11. A slidable shaft 12 extends into and from the hollow portion of the shaft 8, and relative motion between the hollow shaft 8 and the inner shaft 12 is limited to that of an axial character by a pin 13 which is fastened into shaft 12 and protrudes into the slot 11 of the shaft 3. Fastened to the protruding end of the shaft 12 in a plane perpendicular to its axis is a disc 14. Fitted over the shaft 12 is a compression spring 15. Compression spring 15 bears on one end against the end of shaft 8 and on the other end against the disc 14.

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Opposite auxiliary shaft 3 in housing 1 parallel to shaft ti and in an offset position to shaft 8 is a take-off shaft 16 situated, rotatable and also capable of axial motion, within a hollow inward protrusion 17 of the housing 1. The take-off shaft 16 has at its end which is within the housing 1 a disc 18, and fitted over the shaft 16 is a spring 19 in compression between the disc 18 and the housing protrusion 17.

Between the disc 14 on the shaft 12 and the disc 18 on the shaft 16 is a pair of contacting spheres 20 and 21, said spheres 2i) and 21 held rotatably in such a position that their centers are in a line perpendicular to the discs 14 and 18 by a cage 22. The sphere holding cage 22 is affixed to a rectangular ratio control bar 23, said rectangular ratio control bar 23 being slidably held perpendicular to the axis of the main drive shaft 2 within fixed guides 24 and 25 (shown in partial cross section) which are affixed to the housing 1 and extend into it toward the observer. The rectangular ratio control bar 23 is drilled throughout its length and threaded internally as at 26. Within the drilled out portion of the control bar 23 and longer than said bar 23 is an adjusting rod 27. Adjusting rod 2'7 is externally threaded as at 26 in a manner as to engage the corresponding internal threads of the ratio control bar 23. One end of the adjusting rod 27 protrudes from within the ratio control bar toward the cam 5, and affixed upon this end of the adjusting rod 27 is a ball cage 28 in which is partially contained a freely rotatable ball 29. The ball 29 protrudes from the cage 28. A spring 3i? which is around the control bar 23 and in com pression between the stationary guide 25 and the sphere cage 21 keeps the protruding portion of said ball 29 in contact with cam 5. The end of the adjusting rod 27 which is opposite the ball cage 28 is provided with a slot 31, and in line with the slot in the housing 1 is an access opening 32.

The shaft 16 extends beyond the body of the housing 1, and the end of the shaft 16 outside of the housing 1 has a splined portion 33. A ferrule 3 5-, shown in cross section, internally splined to fit the splines the shaft 16 is held in position over the splined end of the shaft 16 by a cap 35, shown in cross section, which is threaded into the housing The ferrule 34 represents the input of a flexible shaft 37 which is affixed to cap 35 by retainer 36, shown in section. The flexible shaft assembly 37 is connected to and actuates a counter device 32% calibrated in knots and tenths.

External to the housing and on main drive shaft 2 is a pulley 39.

The operation of the device is as follows. The pulley 39 is put into rotation from the rotation of a propeller shaft on a boat by a suitable belting means not shown. The rotation thus induced brings two effects. The first effect consists of turning the shaft 8 and its associated parts by means of the medium of the intermeshing gears 35 and lit. The second effect brought about by the rotation of shaft 2 is in the flyball governor and consists of a movement outwardly of the governor weights with an attendant upward movement of the earn 5' in opposition to the force of compression spring 6. The cam 5 being fastened to the governor also undergoes rotation, but this is of no consequence in the operation of the device.

The ball 29 being kept in contact with cam S by the spring acting through the bar 23, it follows that the position of the bar 23 and its associated parts is determined by the diametral dimension of the cam 5 at the point of contact between the ball 29 and the cam 5. Since the diameter of the earn 5 decreases from top to bottom, upward movement of the cam by action of the governor 4 brings about a movement of the bar 23 and its associated parts in the direction of the axis of the shaft 2, that is to the left in the diagram.

The rotation also induced in auxiliary shaft 8 as described brings about rotation of the disc 14 as well. The downward pressure on the disc 14 by the spring '15, and the upward pressure on the disc 18 in conjunction with the two spheres 20 and 21 bring about a system in which rotation of disc 14 causes rotationof disc 18. Theratio between the revolutions of disc 14' and those of disc 13 are determined by the relative distances between the cen ter of disc 14 and the point of contact on the disc of the ball 2% and between the center of disc 18'and the point of contact of the ball 21 and this ratio is determined by the position of the bar 23, which in turn is regulated by the cam 5.

The modified rotation thus induced in disc 18 according to the combined governor and cam action is transferred via shaft 16 and the splined connection 34 thence through theflexible shaft assembly 36 and 37 to the counting mechanism 38.

For calibration of the device the boat on which it is to be used must be run at various speeds and tachometer readings taken at these speeds of the propeller revolutions. The variation of revolutions per knot travelled thus derived determines the shape of the cam 5 for a particular strength of spring 6 and for a particular set of characteristics of the governor 4. Adjustments in the variable ratio transmission are made by turning the threaded adjusting rod 27 within the control bar 23, which for a given position of the cam 5 provides a variable position of the spheres 2t) and 21 either more toward the axis of shaft 8 or more toward the axis of shaft 16. This adjustment may be made with a screwdriver engaging the slot 31 in rod 27 through the access opening 32 in the housing 1.

Since the earn 5 has a larger diameter at the top, which is where the ball 29 contacts it at lower speeds, the overall ratio from propeller shaft to counter is chosen to correspond to the theoretical number of turns of the propeller per nautical mile with the ball 29 in contact with the upper portion of the cam, and with the governor not exerting any effect. As the speed goes up and the propeller efliciency falls oi'i, the cam is made to rise by governor action, and this changes the ratio of the variable ratio transmission in such a way that the turns counting ei ficiency of the device falls oif correspondingly, and the actual relationship between turns registered and miles travelled remains constant. a

I claim:

In a recording log for marine vessels the combination of a rotational take-oh, a flyball governor type means, a variable ratio transmission, both said flyball governor type means said variable ratio transmission driven from said rotational take-off, a cam of modified cylindrical form, said cam linked to and axially displaceable by said fiybali governor type means, a spring-loaded cam follower, said cam follower bearing upon and actuated by saidcam and said'cam-follower being connected to the control of said variable ratio transmission, and a proportionally reading turns registering means, said turns registering means being driven from the output of said variable ratio transmission.

References Cited in the file of this patent FOREIGN PATENTS 7,688 Great Britain Apr. 2, 1908 654,708 France Dec. 7, 1928 864,032 France Ian. 8, 1941

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