US2412605A - Speed adjusting mechanism - Google Patents

Description

G. F. DRAKE SPEED ADJUSTING MECHANISM Filed Feb. 5, 1943 3 Sheets-Sheet l Eiyl,

I %.M ATTORNEYS INVENTOR George Forrest Drake Dec. 17, 1946. DRAKE SPEED ADJUSTING MECHANISM Filed Feb. 3, 1945 3 Sheets-Sheet 2 INVENTOR George Forrest .Dra/ e BY I ATTORNEYS Dec. w, 194% G. F. DRAKE 2,412,605

SPEED ADJUSTING MECHANISM Filed Feb. 3, 1943 3 Sheets-Sheet 5 INVENTOR George Forrest Dre/(e E-44., Kym/21a: ATTORNEYS Patented Dec. 17, 1946 UNITED STATES PATENT OFFICE.

SPEED ADJUSTING MECHANISM George Forrest Drake, Rockford, Ill., assignor to Woodward Governor Company, Rockford, 111., a corporation of Illinois Application February 3, 1943, Serial No. 474,549

11 Claims.

This invention relates generally to mechanisms for adjusting the speed setting of a governor or other regulating device from a remote point of control, and in certain of its aspects relates to improvements in a synchronizing mechanism of the general character disclosed in my copending application Serial No. 525,913, filed March 10, 1944, to which this application is subordinate, said application Serial No. 525,913 being a continuation-in-part of application Serial No. 426,362, filed January 10, 1942, the latter now abandoned.

One object is to combine a speed adjusting mechanism'for a plurality of prime movers with a novel means for effecting automatic synchronization of the prime movers.

A further object is to incorporate in such a combined adjusting and synchronizing control a novel means for rendering the synchronizing control operative and inoperative automatically as an incident to starting and stopping of the manually operable adjusting mechanism.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which Figure 1 is a schematic view and wiring diagram of the improved speed adjusting control.

Fig. 2 is a schematic view of the speed adjuster for one power unit.

Fig. 3 is a vertical sectional view of the speed selecting mechanism.

Fig. 4 is a section taken along the line 4-4 of Fig. 3.

Figs. 5 and 6 are similar views showing different positions.

The invention has been shown in the drawings and will be described herein as applied to the speed control of a plurality of internal combustion engines M and S. It is to be understood, however, that I do not intend to limit the invention by such disclosure nor to the particular illustrated constructions of the various switch, I

governor, motor units and electrical transmitters, I

but aim to cover all modifications, alternative constructions, and uses falling within the scope of the invention as expressed in the appended claims.

The speeds of the engines M and S may be controlled by individual governors ll arranged to actuate the engine throttles or, as shown, to effect the speed regulation byadjusting the pitch of propellers l0 driven by the engines. This may be accomplished by applying hydraulic pressure controlled by the governor II to a servo motor 2 l2 rotatable with the propeller and operating on the follower l3 of a cam ill which, through bevel gear connections, turns the propeller blades on their longitudinal axes.

The governor includes a rotary head l5 pivotally supporting fiyballs l6 having arms I! bearing upwardly against the head l8 of a valve rod l9 which is urged downwardly by an adjustable speeder spring 28. The head I5 is on the upper end of a sleeve 2i journaled inthe governor casing and driven from its lower end through a gear connection with the engine crankshaft 23. The valve rod [9 has spaced lands 24 and 25 thereon coacting with ports in the sleeve 2| and shiftable upwardly by the ilyballs in response to a speed increase above the prevailing speed setting to admit pressure fluid from a supply line 28 to a conduit 29 leading to the rod end of the servo motor cylinder. The servo piston moves to increase the propeller pitch until the valve is again closed as shown in Fig. 2. In response to a speed decrease, the valve rod is lowered permitting the flow of fluid out of the servo through the conduit 29 past the land 25 to the sump. The propeller pitch is thus decreased until the speed reduction has been corrected for.

Oil under the proper pressure is supplied to the line-28 by a, booster pump 30 driven from the rotating sleeve 2i and supplied with oil by the engine lubricating pump 3i.

From the foregoing, it will be apparent that the governor operates automatically through the pitch-changing mechanism to maintain the speed of the engine constant and at a value determined by the load imposed on the flyballs by the speeder spring 20. This load may be adjusted by turning a pinion 32 meshing with rack teeth on a plug 33 which is mounted in the governor for movement axially of the spring.

In accordance with the present invention, the pinion shaft 34 of the governor of the engine M is adapted to be turned by an electric motor 35 mounted on the governor casing and acting through reduction gearing 36. This motor is on the receiving end of an electrical transmittin system controllable from a transmitter located at a, point of manual control remote from the engine. Herein, the motor is of the step type having a permanently magnetized rotor 31 adapted to occupy any one of twelve well-defined angular positions according to the combination of direct current potentials applied to three sets of distributed windings 38 on its stator 39. When the windings are deenergized, the rotor will come to an abrupt stop.

-battery d8 through conductors 58 and t.

Operation of the step motor in one direction or the other is effected by turning the shaft 458 of the transmitter which is a commutator switch t! having angularly spaced segments 62, 58, and 1 3 engaged as shown in Fig. 2 by contacts 55, 56, 45, and 88. These are arranged in pairs respectively connected to the difierent polar terminals ofha T e segments are connected directly to the windings of the step motor 35'through suitable brushes and conductors 5 3. The construction of the step motor is such that as the switch shaft 38 turns in one direction, the windings of the step motor will be energized in successive combinations causing the rotor 67 to follow the movements of the switch shaft. Reverse operation of the motor takes place when the commutator switch is turned in the opposite direction.

The governor of the engine S is similarly adapted for adjustment of its speeder spring by a step motor 52 of the same construction as the motor 35. This motor is, in accordance with one aspect of the present invention, adapted to be energized alternatively either under the control a, of the commutator switch M or of a commutator switch 53 of the same construction also located at the remote point of control and having its parts indicated by corresponding primed reference numbers. The motor 52 may be connected to the segments of the switch 58 through conductors 55 including switches 56 or it may be energized from the commutator switch 85 through conductors 57 and 57', the latter having switches 58 interposed therein. The movable contacts of the switches 56and 59 are connected to the armature of a magnetic relay 58 in a manner such that the switches 56 are closed and the switches 58 are open when the relay coil is deenergized, the condition being reversed when the coil is energized. The battery leads 50 and 5| are extended to the stationary contacts of the switch 53.

In accordance with one aspect of the present invention, one of the engines, in this instance M, is selected as the master, and the speed of the other or slave engine S is matched accurately by operation of the commutator switch 53 in directions and amounts such as to correct for any departure of the slaveengine speed from that of the master. The speed matching is effected by a differential three phase motor or so-called differential Selsyn 68 comprising a thred'phase two pole stator and a three phase two pole rotor having windings 6i and 6|, the rotor being fast on the commutator switch shaft 48'. These windings are energized respectively by small permanent magnet generators 62 and 63 respectively mounted on the engines Mv and S and driven thereby. Generators of the type suitable for this purpose are disclosed in Patent No. 2,071,536. The generator 63 is connected to the rotor winding 6| by conductors 65 including switches 66 while switches 61 are included in conductors 68 leading from the generator 62 to the stator winding 6|.

With both windings energized and the engines M and S running at the same speed, the fre-' quencies of the two current sources will be identical so that the rotor shaft 48' will not turn. When thespeeds of the master and slave engines are difierent, the frequencies of the currents supplied by the respective generators will difier proportionately, and the difierential rotor shaft will turn in a direction determined by which frequency is higher. Such operation will continue until the slave engine has, by operation of the commutator switch 58 and the step motor 52, beenbrought into synchronism with the master M.

To enable the difierential motor 58 to be disabled at certain times as during the adjustment -of the engine speeds under manual control, the

switches 66 and 67 are connected to the armature of a magnetic relay 68 interposed in a circuit extending from one power lead 58 through one or more normally closed manually operable switches 69, a conductor '58, the relay coil 58, one or more normally open switches it connected in parallel, and a conductor l3 connected to the other power lead 5|. When the relay coil is energized by closure of one of the switches ll, the switches 66 and 67 will b closed and the differential motor 68 will be rendered operative. Such operation of the relay also results in closure of aswitch 12 which completes a holding circuit through the relay coil and the switches 69. Thus energization of the relay 68 is maintained until one of the switches 68 is opened whereupon the switches 66 and 67 are opened may be reversed by reversing the current flowthrough the rotor winding. Herein, this winding is energized selectively or deenergized by a magnetic reversing switch I6 operated differentially by the energization of coils 11 and '88. As shown, the switch comprises a frame 19 pivoted intermediate its ends at 88 and adapted to be actuated from opposite ends by the armatures of the magnets 71 and T8.

Projecting from the frame are spring arms 8! which cooperate with stationary contacts to form switches 82 and 83 which are both closed when both of the coils T! and 18 are deenergized. Arms 84 on the frame cooperate with stationary contacts to'form switches 85 and 86 which are both' open when the coils 11 and 18 are deenergized. The stationary contacts of the switches 82 and 85 are connected by a conductor 81 to one ter-.

minal of the rotor winding while the contacts of 4 the switches 83 and 86 are connected to the other terminal by a conductor 88. A conductor 89 extendsfroni the arms 84 to one battery lead 58 while a conductor 90 connects the other arms 8| to the other battery lead 5|.

The coils I1 and 18 are connected together at one end and their insulated terminals are joined by conductors 9| and 82 to contacts 93 and 84 of two control switches 95 and 96 (Fig. 4) having a common intermediate contact 91 connected by a conductor 98 to the battery lead 50. It will be apparent that when the coil 11 is .energized, the frame 18 will .be pushed downwardly and tilted counterclockwise about the center 80 opening the switch 82 and closing the switch 85 so that current flows through the motor 13 from the lead 58, conductor 89, switch 85, conductor 81, rotor 15, conductor 88, and switch 83 to the lead 5!. Current flows in the reverse direction through the switches 82 and 86 when the coil 18 is energized tilting the frame 79 clockwise. When both coils TI and 18 become deenergized, the switches 82 and 83 both close thereby shortcircuiting the rotor 15 to produce abrupt stopping of the commutator'switch 4| and therefore of the step motors controlled thereby. I

In accordance with the present invention, the motor is started in one direction or the other by movement of a manually operable member I to a position corresponding to a newly selected speed setting where the member is retained, frictionally in this instance, and operation of the motor continues until the governors II have reached the selected speed setting whereupon the motor will be stopped automatically. While the manually operable. member may take various forms, it is shown herein as comprising a hand lever fast on a shaft IOI which is journaled in and projecting from one wall of a casing I02 which houses the motors 00 and I3, the commutator switches AI and 53, and the-relays 58, 68, and I6. This lever may be mounted in any convenient location within the reach of the operator or pilot.

Rotatable with the shaft IOI is a disk I03 which is urged by a, compression spring I03 against a stationary'plate I04 to create the friction necessary to hold the lever I00 inany-selected position while permittin the lever to be swung manually in either direction. A pointer I05 on the lever coacts with a scale 606 to indicate the speed setting'in revolutions per minute or other units Mounted on an arm I01 projecting upwardly from the disk I03 are the common contacts 9! which ar disposed between spaced lugs I08 carrying the contacts 93 and 94 and pro jecting rearwardly from an upwardly projecting arm I09. The latter is on a loose bushing IIO on the shaft WI and carries the pivot III of a bell crank II2. A roller II3 on one arm of the bell crank constitutes the follower of a heartshaped cam II4 having gradual rises H5 and H6 on opposite sides of a notch II!. A spring II9 acting between the bell crank and the arm I09 holds the roller in contact with the cam surface. The arrangement is such that when the roller is disposed in the notch, the contacts 91 are disposed out of engagement with the contacts 93 and 94 as shown in Figs, 4 and 6. When the roller is engaging either incline, the contacts 93 and 94 are shifted relative to the arm I01 and one or the other is pressed against one contact 91. The cam H4 is fast on a sleeve H9 which carries a gear I I9 driven through reduction gears I20 to I21 from a pinion I20 on the shaft I40 of the motor I3. The direction of this drive is always such as to move the notch II! of the cam back toward the follower roller-I I3.

It will be observed that the two arms I01 and M9 are swingable about a common axis and are adapted for the limited degree of relative movement required to actuate the switches. The cam H4 and its follower provide a connection between the arm I09 and the cam shaft which is adapted to yield in either direction after closure of one switch and permit both arms to move in unison to the selected switch position. Thereafter, the

I cam operates to determine the extent of separation of the motors and therefore the amount of adjustment of the speed regulator or governor. This action is obtained by correlating the gear trains and other parts so that the range oi motion of the hand lever corresponds to the range of speed adjustment of the governor. That is to say, a given change in the lever position will,- under the control of the switches and the transmitting system, produce a proportional change in the movement of the governor adjusting plug. In this way, the pilot may increase or decrease the en- 94 and carry the latter and the arm I09 alon with the lever, the roller II3 riding up the incline II5 after the contact engagement occurs.

The relay coil I8 and the relay 58 are thus energized to start the motor and also connect the step motor 52 tothe commutator switch 4|. The motor runs the switch shaft 40 in a direction to change the speed settings of both governors II to correspond to the newly selected speed and at the same time .to turn the cam H4 in a direction to follow up the movement of the arm I0 I and advance the notch II'I toward the roller II3. In .this operation, the selected position of the lever I00 and the contact 94 are maintained by the friction created between the disk I03 and the plate I04, and the incline II5 acts on the bell crank H2 to prevent opening of the switch 99 until the cam H0 has been turned sufficiently to present the notch iII opposite the roller II3. As the latter becomes centered in the notch as shown in Fig. 6 with the lever in its new position, the arm I09 is moved by the spring II 9 to cause the contact 94 to disengage the lever contact 91 thereby opening the switch 9E5 and stopping the motor I3. Thus, the extent of motor operation is determined by the selected position of the lever I00 and this without the necessity of the pilot holding the lever to retain the selection.

The same operation takes place when a reverse speed setting is selected by moving the lever I00 in the opposite direction. In that case, the switch is closed and the relay coil 11 i energized along with the relay 58 so that the motor 13' and the step motors 35 and 52 run reversely changing the speed settings of the governors correspondingly until the incline I It has moved past the roller I I3 and the latter has become centered in the notch III. At this time, the switch 95 opens, stopping the motor I3 and simultaneously disconnecting the step motor 52 from the commutator switch GI while connecting it to the commutator switch 53. By actuating the relay switches 56 and 59 automatically as above described in response to energization of the motor I3 for operation in either direction, the adjusting step motors for both the master and slave govemors will be adjusted simultaneously and all of the associated engines will be brought rapidly to the speed selected by positioning of the single lever I00. Thus, the lever, the step motors 35 and 52, .the commutator switch 4 I, the motor I3, and the control for the latter may be utilized as a remotely controlled mechanism for adjusting the speeds of all of the engines during take-off and landing, or to change the engine speeds to be maintained during automatic synchronizing.

Such synchronizing may be effected in the present instance simply by the addition of the commutator switch 53, the differential motor 60 and the generators 62 and 63. These become effective when the switches 66 and 61 are closed thereby completing the connections from the generators to the differential motor 60 whereupon the slave step motor 52 will be operated automatically to adjust the slave governor and match stored-automatically when the selected master engine speed adjustment has been completed and this, without further attention by the pilot.

To disable the automatic synchronizing mechanism manually, it is only necessary to open one of the switches 69 and thereby interrupt the holding circuit for the relay 68. The resulting deenergization of the latter disconnects the Selsyn SE from the generators 62 and 63 until one of the switches H is again closed to reenergize the relay 68 and reestablish automatic synchronizing.

It will be observed that the number of slave engines S to-be synchronized with the master M may be increased as desired simply by multiplying the number of step motors, commutator switches, differential motors, generators, relays 53 and 68, these being connected in the control circuits in the same ways as the corresponding units shown.

I claim as my invention:

1. A control for matching the speeds of slave and master power units each having an adjust-- able speed regulator, said icontrol comprising, in combination, slave and master step motors each arranged to actuate one of said regulators, a master commutator switch operable to control the master step motor and connectable selectively to the slave step motor, a second commutator switch connectable selectively to said slave step motor, a differential motor'for driving said second commutator switch and operable selectively in accordance with the differences in the speeds of said master and slave units, a reversible rotary electric motor driving means for said master commutator switch, a manually operable member adapted to' remain in a manually selected position, switching means operable in response to a change in the position of said member to start said driving means and then continue the operation thereof until said master speed regulator has been adjusted to a setting corresponding to that selected by said member, and means operable to effect energization of said slave step motor commutator switch in accordance with diflerences in the speeds of said master and slave units, reversible electric motor driving means for said master commutator switch, a manually operable member movable independently of said regulators, switching means operable in response to a change in the position of said member to start said driving means in a corresponding direction and then continue the operation thereof until said master speed regulator has been adjusted to a setting corresponding to that selected by said v 8 member, and means operable to shift the control ofsaid slave step motor to said master commutator switch during operation of said driving means in either direction and to said second commutator switch when said driving means is idle.

3. A control for matching the speeds of slave and master power units having individual speed regulators, said control comprising, in combination, slave and master step motors each arranged to actuate one of said regulators, a master commutator switch operable to control the master step motor, a second. commutator switch, means automatically responsive to difierences in the speeds of said master and slave units to actuate said second commutatorswitch in a direction to correct for such difierences, motor driven means for driving said master commutator switch,

means operable selectively under manual control to operate said driving means, and means operable automatically to snift the control ofsaid slave step moton to said master commutator switch during operation of said driving means and to said second commutator switch when said driving means is idle.

e. A control for matching the speeds of slave and master power units having individual speed regulators, said control comprising, in combination, slave and master step motors each arranged I to actuate one of said regulators, a master commutator switch operable to control the master step motor, a second commutator switch, means automatically responsive to differences in the speeds of said master and slave units to actuate said second commutator switch in a direction to correct for such difierences, motor driving means for said master commutator switch, means operable selectively under, manual control to cause operation of said driving means, and means operable automatically'to cause energization of said slave step motor from said master commutator switch alone during operation of said driving means.

5. A control for matching the speeds of slave and master power units each having an individual speed regulator, said control comprising, in combination, remotely controlled means for adjusting the master speed regulator, means automatically responsive to differences in the speeds of said master and slave units to adjust the slave speed regulator and correct for such difierences, and means operable automatically during adjustment of said master speed regulator to-disable said last mentioned means and cause adjust-- ment of the slave speed regulator in unison with the master regulator.

6. A control for matching the speeds of slave and master power units having individual speed regulators, said control comprising, in combination, slave and master motors each arranged to actuate one of said regulators, synchronizing means automatically responsive to difierences in the speeds of said master and slave units to actuate the slave motor in a directionto correct for such differences, motor driving means for controlling the operation of said master adjusting tion, slave and master receiving motors arranged to actuate the respective regulators, a master electrical transmitter operable to energize the master receiving motor and cause rotation of the latter in unison with the transmitter, a second transmitter, means automatically responsive to diflerences in the speeds said master and slave units to actuate said second transmitter in a direction to correct for such differences, motor driving means for operating said master transmitter and cause operation of said master motor selectively in one direction or the other, means operable selectively under manual control to cause operation of said driving means, and means operable automatically to cause energization of said slave receiving motor from said master transmitter alone during operation of said driving means.

8. A control for matching the speeds of slave and master power units each having an adjustable speed regulator, said control comprisin slave and master receiving electric actuators arranged to actuate the'respective regulators, an

' in unison, an electric motor, switching means controlling the operation thereof, means including a manually operable member shiftable selectively to difierent positions corresponding to speeds of said power units and operable, when moved to a new position, to actuate said switching means and energize said motor for operation of said receiving motors by said transmitter in a direction to move said regulators to settings corresponding to said speeds, follow up means actuated by said motor and actuating said switching means to continue the operation thereof until the regulator setting selected by said member has been attained, mechanism automatically responsive to a difference in the speeds of said master and slave power units to energize said slave smed regulator in a direction to correctior such difference, a relay energized and deenergized under the con trol of said switching means during operation thereof by said member and said follow up means, and means actuated by said relay to disable said mechanism until a new speed setting of said regulators selected by said member has been attained and then to render said mechanism again operative.

9. A control for matching the speeds of slave and master power units each having an adjustable speed regulator, said control comprising slave and master receiving electric actuators arranged to actuate the respective regulators, an electrical transmitter operable to energize said receiving actuators and cause operation of the latter to adjust said master and slave regulators in unison, electric motor driving means, means including a manually operable member shiitable selectively to different positions corresponding to speeds of said power units and operable, when moved to a new position, to energize said driving K means and cause operation of said receiving m0- tors by said transmitter in a direction to move said regulators to settings corresponding to said speeds, follow-up means actuated by said driving means for continuing the operation thereof until the regulator setting selected by said member has been attained, mechanism automatically responsive to a difference in the speeds of said master and slave power units to energize said slave speed regulator in a direction to correct for such difference, and means operable automatically to maintain said mechanism disabled during operation of said driving means and then to render said mechanism again operative.

10. A control ior matching the speeds of slave and master power units each having an adjustable speed regulator, said control comprising slave and master receiving electric actuators arranged to actuate the respective regulators, an electrical transmitter operable to energize said receiving actuators and cause rotation of the latter to adjust said master and slave regulators in unison, electric motor driving means, means including a manually operable member shiftable selectively to different positions corresponding to speeds of said power units and operable. when moved to a new position. to energize said driving means and cause operation of said receiving motors by said transmitter in a direction to move said regulators to settings correspondi g to said speeds, mechanism automatically responsive to a diiierence in the speeds-of said master and slave power units to ener ize said slave speed regulator in a. direction to correct -for such difference and maintain said units svnchronized. and electric switching means actuated automatically as an incident to movement of said member to select a new speed setting to disab e said mechanism until such speed setting of said re ulators is attained and then to render said mechanism again operative.

ii. A control for matching the speeds of slave and master power units each having an ad ust able speed regulator. said control comprising slave and master receiving electric actuators ar= ranged to actuate the respective regulators, an electrical transmitter operable to ener ize said receiving actuators and cause rotation of the latter to adjust said master and slave re ulators in unison, means manually operable to cause actuation of said transmitter and said receiving motors in a direction to move said regulators to a selected speed setting, mechanism automatically responsive to a difference in the speeds of said master and slave power units to ener ize said slave speed regulator in a direction to correctior such diflerence and maintain said units synchronized, and means actuated automatically as an incident to actuation of said manually operable means to select a new speed setting to disable said mechanism until such speed setting oi said regulators is attained and then to render said mechanism again operative.

' GEORGE FORREST DRAKE.

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