US2321025A - Propeller control mechanism - Google Patents

Description

June 8, 1943.- J; H. HAMMOND, JR

PROPELLER CONTROL MECH ANISM 2 Sheets-Sheet 1 Filed Oct. 10, 1941 Em bu mm M .2 E

KMFUZ JmDk INVENTOR JOHN HAYS HAMMOND,JR.

ORNEY June 8, 1943. J. H. HAMMOND, JR 2,321,025

PRQPELLER CONTROL MECHANISM Filed OCT. 10, 1941 2 Sheets-Sheet 2 INVENTOR 1 JOHN HAYS HAMMOND,JR

-BY m E.E.

Patented June 8, 1943 UNITED S'TATES'PATENT OFFICE 2,321,025 PROPELLER coN'moL MECHANISM John Hays Hammond, Jr., Gloucester, Mass. Application October 10, 1941, Serial No. 414,488

'1 Claims.

the rate of change of pitch of the propeller blades in accordance with the rate of change of fuel consumption.

The invention also consists in certain new and original features of construction and combinations of parts hereinafter set forth and claimed.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and Zurich, Switzerland, the details of which form no part of the present invention and are accordingly not specifically set forth herein. This mechanism, in general comprises a rod l9 slidable longitudinally within the shaft l and connected to control the pitch of the blades l3. The rod advantages, the mode of its operation andlthe manner of its organization may be better understood by referring to the following description, taken in connection with the accompanying drawings forming a part thereof, in which Figure 1 illustrates diagrammatically the system as applied to a fuel consumption meter of the prime mover, and

Figure 2 is an enlarged view of the mechanism of the fuel consumption meter.

Like reference characters denote like parts'in the several figures of the drawings.

In the following description and in the claims parts will be identified by specific names for convenience, but they are intended to be as generic in their application to similar parts as the art will permit.

Referring to the accompanying drawings, and more particularly to Figure 1, the hull of a marine vessel is indicated at II. This vessel is shown as driven by means of a propeller I2 which is provided with adjustable blades [3. The propeller I2 is attached to the end of a hollow shaft l5 which passes through an outboard bearing IS. The shaft I5 is driven by a prime mover 20 which may be of any desired type but is preferably of the Diesel engine type and is provided with a governor, not shown, for maintaining a constant speed of rotation.

The blades l3 are connected to a variable pitch mechanism l8 which may be of any well known and standard construction such as that manufactured by the Escher-WySs Company of.

I9 is actuated by a piston 21 in afluid pressure cylinder 21a. Fluid for actuating the piston 21 is supplied by a pump 26 through a control valve 25 and a distribution valve 25a which communicates with the cylinder 21a through ducts, not shown, in the shaft l5.

A motor 2| rotates a worm 22 which operates to move the upper end of a floating lever 23,

which, in turn, is pivoted to the end of a valve rod 24 which controls the valve 25. The piston 21 is connected by a rod 28 to a collar 29 which is slidably mounted on the shaft l5 and engages the lower end'of the lever 23 so that the position of this end of the lever corresponds to the pitch of the blades l3. I The upper end of the lever 23 is connected by a wire 30 to an indicator 3| which shows the pitch at which the blades l3 are set, Stops- 32 are provided for limiting the maximum'and minimum pitch of the blades [3. The fluid pump 26 is driven either by a motor 33 or abelt 35 from the shaft l5. A reservoir 36 and a supply tank 31 are provided for the necessary fluid.

It is to be understood that other pitch control devices may be employed in place of that referred to above, for varying the pitch of the propeller blades l3 in response to actuation of the motor 2|. A particular type is shown for purposes of illustration only.

The engine 26 is supplied with fuel from a supply tank 40, the fuel from which passes thru a pipe 4| to a fuel consumption meter 42, to be described, from which it passes thru a pipe 43 to the fuel pump 45 of the engine 20.

Referring to Figure 2 the fuel consumption meter 42 is shown in detail ascomprising in general two fuel weighing devices 46' and 41, two control valves 48 and 49, a distribution valve 50, two pitch control mechanisms 5| and 52 and a time controlled switching device 53.

The fuel weighing devices 46 and 41 comprise two fuel tanks 55 and 56 which are mounted on two shafts 51 and 58 which are slidably mounted in brackets 59 attached to a base plate 60. Secured to each of the shafts 51 and 58 is a collar 6| between which and the corresponding bracket 59 is a compression spring 62. Mounted on the shafts 51 and 58 are pins 63 and 64 respectively. The pin. 63 cooperates with two levers 65 and 65 which are'pivoted at 31 and 5 to the base 68 and tend to be rotated in a clockwise direction by springs and". Secured to but insulated from the levers 65 and 66 are two contact arms 12 and 13.

The pin 64 cooperates with two levers 15 and 16 which are pivoted at 11 and 18 to the base 68 and tend to be rotated in a counter-clockwise direction by springs 15 and 80. Secured to but insulated from the levers 15 and 16 are contact arms "and 32 respectively. Each of the contact arms 12 and 8| selectively engages a set of six segments 85-90, mounted on but insulated from an are shaped member 92, I

which is slidably mounted in brackets 93 and 04 attached to the base 68. The brackets 03 are provided with clamping screws 35 for holding the members 52, and contacts 8580 in any desired position. Pointers 51 are attached to the members 52 and register on scales 88 secured to the base The segments 85am! 30 of each set are connected by flexible conductors to two conductors Ill and III which in turn are connected to the reversing windings of the motor 2| (Figure 1).

Thesegments 86 and 81 are connected by flexible conductors to two resistors I 02 and I03 which is turn are connected to the conductor I00. The segments 88' and 88 are connected by flexible conductors to two resistors I05 and I06 which inturn are connected to the conductor IN. The common lead of the reversing windings of the motor 2| is connected thru a battery I01 to the blade of a three position switch I08. The center contact of this switch is connected to a conductor I09, the lower contact to the conductor Ill andthe upper contact to the conductor MI. The fuel supply pipe II is connected to two branch pipes H0 and III which feed fuel at suitable times to the two tanks 55 and 56 respectively. The control valves 48 and 43are located in the supply pipes I I0 and III and control the flow of fuel to the two tanks 55 and 56 respectively. Each of the control valves 48-and43 comprises a casing H2 in which reciprocates a valve stem 3 provided with a port ll5. The valve stem 3 forms the core ofa solenoid H6 and has secured thereto a collar 1. Surrounding the valve stem 3 and located between the sole.- noid' III and the collar 1 is -a compression spring I I8 which tends to hold the valve in the closed position. 7 f

The two tanks 55 and 56' are connected by flexible tubing I20 to the distribution-valve 50 which comprisesa casing I2I in which is rotatably moimted a valve I22 provided with 'a-port m. The valve 2: is secured to an arm I25 the end oi which'is connected .to the core I26 of a solenoid I21. Fastened to the core I26 is a collar I28 between which and thes'ol'enoid I21 is 10- Y and I54.

one side of the winding oi the solenoid I21, the other side of which isconnected to the contact I40. The commutator I36 is provided witha sector I42 of conducting material, which at suitable 5 times, engages four contacts I45, I46, I41 and I48. The contacts I45 and I48 are connected to the conductor I03. The contacts I46 and I41 are connected to the contact arms 12 and 8| respectively. The commutator I31 is provided with a 10 sector I50 of conducting material, which at suitable times, engages four contacts I5I, I52, .I53 The contacts I52 and I53 are connected thru a battery I55 to one side of the windings of'the solenoids H6. The contact I5I is-conl5 nected to a contact I56 which normally engages the arm 13 and the contact I54 is connected to' a contact l51 which normally engages the arm 82. Two contacts I58 and I59 which normally engage the .arms' 13 and 82 are connected to the 20 other sides of the windings of the solenoids II6.

Operation In the operation of this invention the pitch of the blades I3 is flrst set at the normal operating 25 angle for the speed at which it is desired to operate the vessel. The setting of the propeller blades I8 is accomplished by .movlng the blade of the switch I08 into the lower or upper position which will cause the motor 2| to move the upper end of the lever 23 to the left or right toincrease ther control automatic in response to operation of the fuel consumption meter 42.

The operation of the fuel consumption meter may be considered as divided intotwocycles of,

- for example, fifteen minutes each which are controlled by the timed switching device 5:. During one such cycle the fuel is used from the tank 56,

the consumption during a given interval is measured, and the pitch control motor-is actuated by the control mechanism 52 to change the pitch in a manner to correct for any deviation in consumption from a predetermined value. During the next cycle the measurement and control are efl'ected by the tank and the control mechanism 5|, while the tank 56 is refilled. The pitch 5 is thus varied at intervals in accordance with the integrated fuel consumption which is a I measure of the power being developed, and in a sense to maintain constant power.

The condition of the apparatus-shown in Fig- 55 ure 2 is that assumed by the mechanism at the beginning of one of these cycles with both control valves 48 and 48 closed.. The tank 56 has just been filled with a predetermined amount-of fuel (oil) and the valve 50 has just been operated 60 by energization of the solenoid I21, so that fuel cated. a compression spring I23. A tension -from the'tank 56, passes thru the flexible tube spring I30 is secured to theend'of the arm I25, and tends to rotate the valve I22 in a clockwise direction. g

The time controlled switch 53 comprises a driva clockwise direction at a predetermined uniform rate of speed, which for example may be" contact I38 is connected thru a battery I 4 l to 7g I20, port I 23 and pipe 43 to the fuel pump 45 of the engine 20.' The pitch control mechanism 52 is'in its inoperative condition, as the 'contact' I41 is on the insulating position of the commuing mechanism I32 which rotates a, shaft I33 in .tator I36. Fuel has been used from the tank 55, which'is the measuring position and the pitch control mechanism 5| is in operative. condition as the contact I46 is on segment 2.. Thevari- 7 able pitch mechanism I8 does not operate, however, because the contact 12 is shown as on the insulation between the segments 81 and-88, a position indicating that""the full consumption from the tank 55 during the preceding cycle cor-.

responds to the predetermined value;

quickly fills up.

The two members 92 have been set to positions corresponding to the predetermined amount of fuel which should be consumed in the operating cycle under normal operating conditions, 1. e., for a given power load at constant propeller R. P. M., as indicated on scales 88 by pointers 91. The members 82 are held in these positions by tightening screws 95.

As the shaft I33 rotates in a clockwise direction from the position shown,'the segment I42 disengages the contacts I45 and I48 after a predetermined interval such as two minutes thus putting the pitch control mechanism I inan inoperative condition. On further rotation of the shaft.l33 the segment I50 engages the contacts I5I- and I52 thus closing a circuit from the battery I55 thru the solenoid II8 of the valve 48 which is thereby opened, allowing fuel to flow through the supply pipe 8 to the tank 55 which As it does so the tank 55 together with the shaft 51 moves downwardly against the action of the spring 82. This motion continues. until the pin 83 engages the lever 88, rotating it in a counterclockwise direction, thus opening the circuit between the contacts I58 and I58 which causes the solenoid M8 to be deenergized and the valve 48 to close under the action of the spring II8. The'tank 55 is now full and contains a definite predetermined weight of fuel oil. A

As the shaft I33 continues to rotate the segment I50 will move out of engagement with the contacts I51 and I 5|, thus opening. the circuit of the solenoid II8 of the valve 48 and allowing the valve 48 to close. At the end of the cycle the segment I38 will move out of engagement with the contacts I38 and I40 thus deenergizing the solenoid I21. This will allow the valve .122 tobe rotated in a clockwise direction under the action of the spring I30 which will disconnect the pipe 43 from the tank 55 and connect it to the tank 55. At the same time the segment I42 will engage the contacts I41 and I48 thus putting the pitch control mechanism 52 in an operative condition.

During the cycle in which the tank 58 is connected to the fuel pump 45, a certain quantity of fuel oil is consumed by the engine 20. This lightens the load on the shaft 58 which moves upwardly under the action of the spring 82 until a position of equilibrium is reached depending on the weight of fuel consumed during the cycle.

As the shaft 58 moves upwardly the pin 84 engages the lever 15 causing it. together with the contact 8| to rotate in a clockwise direction. If normal operating conditions were maintained during the cycle the amount of fuel consumed would be exactly equal to the predetermined amount, as indicated by the pointer 91 on the scale 88. Under these conditions the contact 8I rests on the insulation between the segments 81 and 88 at the end of the cycle when the contacts I53 and I54 ar closed by the segment I50 and the pitch varying mechanisms I8 is not operated.

If, however, the operating conditions are unfavorable such as due to head winds or a heavy sea, the fuel consumption increases and more than the theoretical amount of fuel is consumed, thus decreasing the weight of fuel in the tank 58 so that the shaft 58 moves farther up, which in turn causes the contact 8| to engage segment 88, for example. This closes a circuit from the battery I01 thru the resistor I05 to the motor 2| causing it to rotate slowly in a direction to move the upper end of the lever 28 to the right, which allows fluid under pressure to pass from the pump 28 to the cylinder 211: by means of the ducts in the shaft I5. This fluid actuates the piston 21, which, by means of the rod I9 causes the propeller blades I3 to slowly decrease their pitch.

This operation of the motor 2! continues for a brief interval of time, which, for example may be two minutes, at the end of which the segment I42 will move out of engagement with the contacts I41 and I48 thus stopping the variable pitch mechanism I8, and completing the cycle of operation for the tank 58 and associated mechanisms.

If under favorable conditions the fuel consumption during the cycle should decrease, the weight of fuel consumed during this interval would be less and shaft 58 would not move up so far, so that the contact 8| would engage the segment 81, which would complete a circuit to the motor 2| to cause the blades I3 to slowly increase their pitch.

If conditions change more quickly so that somewhat more or less fuel is consumed during the cycle, .the contact 8I will engage either of the segments 89 or 88. Under these conditions either the resistor I08 or the resistor I02 will be thrown in circuit with the motor 2|. As resistors I08 and I02 have less resistance than resistors I05 and I03, the motor 2I will be caused to rotate faster, thus changing the propeller r pitch more rapidly to take care of the more rapidly changing conditions.

If conditions change still more quickly so that considerably more or less fuel is consumed during the cycle, the contact 8| will engage either of the segments or 85. In this case no resistance will be thrown in the circuit of the motor 2I audit will rotate at its maximum speed, thus changing the propeller pitch at a maximum rate. The stops 32 are provided so that the propeller pitch is prevented from exceeding certain limits beyond which it could not operateefliciently under any conditions.

As the shaft I33 continues to rotate the segment I50 will engage the contacts I53 and I54.

thus closing a circuit thru the solenoid II8 of the valve 48 which will cause this valve to open and allow fuel oil to enter the tank 58. As the tank 58 fills with fuel it will move downwardly together with the shaft 58 until the pin 84 engages the lever 18, thus breaking the circuit to the solenoid H8 and closing the valve 48.

v Further rotation of the shaft I33 will cause the segment I38 to engage the contacts I38 and I40 which will energize the solenoid I21 to rotate the valve I22 in a counterclockwise direction to disconnect the tank 55 from the pipe 43 and connect the tank 58 to said pipe. At the same time the segment I42 will engage the contact I45 and I48 to put the pitch control mechanism 5I in an operative condition to control the pitch of the blades I3 in a manner already described, but in accordance with the fuel consumption from the. tank 55. This completes the cycle of operation for the tank 55 and its associated mechanism.

By the system above described the pitch of the propeller blades I3 is varied at predetermined intervals by amounts proportional to the integrated variation of fuel consumption from normal during this interval. This causes the propeller to operate so as to maintain the average rate of fuel consumption of the engine 2. constant under varied conditions. The rate of change of pitch will vary in accordance with the rate of change of fuel consumption.

While the fuel weighing devices shown here are of the spring operated type it is to be understood that weight operated mechanisms may be used it found desirable. It is also to be understood that while weight operated meansare shown for I measuring the amount of fuel consumed the invention is not to be limited thereto but may employ other means for measuring the amount of fuel consumed, such for example as volume measuring devices which would operate the shafts 51 and 58.

Although only a. few of the various forms in which this invention may be embodied have been shown herein,- it is to be understood that the invention is not'li'mited to any specific construction but may be embodied in various forms without departing from the spirit of the invention or the scope of the appended claims.

' What is claimedis:

1. In a system for driving a vessel, a propeller having blades, means controllingathe pitch of said blades; a liquid fuel actuated motor driving said propeller, a fuel line supplying liquid fuel to said motor, a fuelmeter connected in said fuelisupply having blades, means contro i the pitch of said blades, an internal combustion motor driving said propeller and having means maintaining a constant speed of rotation, means measuring the fuel consumption of said motor over predetermined intervals of time, and means actuated at the end of each of said predetermined intervals of time and responsive to variations in said fuel consumption from a predetermined normal value during said intervals, to actuate said pitch control means so as to vary the pitch of said blades in a manner to compensate for said variation in fuel consumption.

5. The invention set forth in claim 4 in which the pitch control means isactuated for predetermined periods of time and at, speeds determined by the amount of variation of fuel consumption from said predetermined normal value during the preceding measuring period.

6. The invention set forth in claim 4 in which the measuring device includes means measuring the loss of weight of fuel due to fuel consumed during the predetermined period of time, and the pitch control means is actuated at a speed determined by the direction and amount of deviation of said-loss of weight from a predetermined normal value.

7. In a system for drivin a vessel, a propeller having blades, means controlling the pitch of said blades, a liquid fuel actuated motor driving said propeller, means measuring the fuel consumption of said motor over predetermined intervals of time and means actuated by. said last means in response to variations in fuel consumption during said intervals of time from a predetermined normal fuel consumption to actuate said pitch control means so as to vary the pitch of said blades in a manner to compensate for said variations in fuel consumption.

JOHN HAYS HAMMOND, J R.

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