US2727579A - Blade pitch control mounted on propeller hub - Google Patents

Description

Dec. 20, 1955 N. R. RICHMOND 2,727,579

BLADE PITCH CONTROL MOUNTED 0N PROPELLER HUB Filed March so. 1949 s Sheets-Sheet 1 In were 30 [liaison llz'c& mama? Dec. 20, 1955 N. R. RICHMOND BLADE PITCH CONTROL MOUNTED ON PROPELLER HUB Filed March 30, 1949 3 Sheets-Shget 3 w Mm\ IIIIIIIIIIII/IL Invewioz liaison R.Rz'c%maua2 197M 5 fliioa ney United States t ntio BLADE PITCH CONTROL MOUNTED N PROPELLER nun Nelson R. Richmond, Thompso'nville, Conm, assi'gnor to United Aircraft Corporation, East Hartford, Comn, a corporation of Delaware Application March 30, 1949, Serial No. 84,269 6 Claims. (Cl. 170 -1601) This invention relates to an improved propeller construction and particularly to an improved self-contained propeller having the propeller controls supported on a non-rotating support journalled on the propeller hub.

An object of this invention is a propeller-control uhit including a propeller-carried non-rotating control system.

A further object is a propeller-control unit including means for accurately positioning the control system with respect to the propeller.

A still further object is a non-rotating hydraulic control system including a governor and pump journalled on a propeller hub.

Other objects and advantages will be apparent from the specification and claims, and from the accompanying drawings which illustrate what is now considered to be a preferred embodiment of the invention. 1

Fig. 1 is a side view partly in section of the improved propeller-control unit.

Fig. 2 is an end view, partly in section, of the control unit, looking away from the propeller.

Fig. 3 is a schematic diagram of the propeller pitch changing mechanism.

Fig. 4 is an end view of the outerbeariiig race of the transfer mechanism and control. unit support.

Fig. 5 is a section showing means for attaching the outer bearing race of the transfer mechanism to the control unit casing.

The propeller-control unit disclosed in this application is an improvement in the construction shown in' Erle Martin Patent No. 2,619,182, issued November 25, 1952. The propeller structure is substantially the same as that shown for the inboard propeller of Patent No. 2,619,182. The controls are also substantially the same as the controls in that application but in the present construction the controls are mounted directly on the pr opellei hub so as to form with the propeller a unitary propeller-control.

unit which may be assembled on and removed from the propeller shaft as a unit and may therefore be com pletely assembled and adjusted on the bench or in' the shop before being mounted on the airplane and which will not require adjustment as part of the procedure of installing the propeller on the airplane. Another advan tage of the present construction is that by mounting the controls on the hub of the propeller, the controls" will move with the propeller in its axial movements caused by thrust, etc., and such movements will not aifect the relation. between the control and: the propeller so as' to cause a change in propeller pitch andthus adversely affect the governing and pitch control. Although a unitary propeller-control unit is provided; the advantages of a stationary control and a stationary oil reservoir are retained.

As shown in-the accompanying drawings-, thepr'op lei coritrol unit comprises apropelier indicated ge erally at 1'0 and a control unit indicated generally; 12. The pro. peller-control unit is n't'ou'ritd as a litiit on a pr dpeller 2 shaft 14 supported in and driven by an engine indicated generally at 16. The propeller which is substantially the same as the inboard unit of the dual rotation propeller shown in Erle Martin Patent No. 2,619,182, referred to above, comprises a hub 18 having an inboard extension 20 mounted on shaft 14 and positioned by the usual cones 22 and splines 24 for rotation about the propeller axis 26. Blades 28 are rotatably mounted in hub 18 for pitch changing movement and are actuated in their pitch changing movement by a vane motor 30 having relatively movable parts, with one part secured to the propeller hub and the other part secured to the propeller blade and located in the shank of each propeller blade as set forth in more detail in Patent No. 2,533,415 referred to in Patent No. 2,619,182. Hydraulic fluid is pumped from a sump 32 mounted on and rotating with the hub 18 by pumps 34 into a conduit 36 leading to a follow-up valve indicated generally at 38. Pumps 34 are carried by and rotate with hub 18 and are actuated by a normally stationary cam 40 carried on one end of a sleeve 42 to increase the pressure of the hydraulic fluid and supply this pressure fluid to the follow-up valve 38 also carried by and rotating With hub 18. Fluid is led from valve 38 through suitable conduits 44 and 46 to the vane motor 30. Valve 38 is so constructed that when pressure fluid is supplied to one side of the vane motor, say through conduit 44, the other side of the vane motor is connected through valve 38 with the sump or reservoir 32 to permit oil to drain from that other side.

The several blades 28, there being four in the propeller shown in Figure 1, are geared together by a connecting gear 48 for equal and simultaneous pitch changing movement. A follow-up mechanism indicated generally at 50 is gear driven from connecting gear 48 and serves to position one part 52 of the two-part follow-up valve 38 in accordance with the pitch of the propeller. The other part 54 of the two-part valve 38 is positioned by control mechanism described below. Due to the follow-up feature of this valve, each position of valve part 54 defines a colresponding propeller pitch when the valve is in a neutral position, i. e., when the valve is not introducing fluid to either side of the vane motor 30 to change the pitch of the propeller. An extension 56 of valve part 54 is positioned by a stationary thrust plate 58. Extension 56 being carried by the propeller hub slides around the face of thrust plate 58 as the propeller rotates.

Hub extension 28 has a sleeve 60 carrying a gear 62 pinned to the inboard end by means of a pin 64. Sleeve 42 is rotatably mounted on the inboard extension 20 by roller bearings 66 and 58. Sleeve 42 is held against axial movement relative to hub extension 20 by segmental shoes 70 fitted into slots in sleeve 60 and sliding in a groove 72 in the inner surface of sleeve 42. Sleeve 60 being pinned to shaft 14 thus secures sleeve 42 against axial movement. The entire control mechanism 12 is mounted, by means that will be presently explained, on sleeve 42 and is, therefore, rotatably mounted on the hub 18 and held against axial movement with respect to the hub. The control mechanism comprises a casing 74 on which the various control elements such as the governor indicated generally at 76, the auxiliary motor indicated generally at 78, the servomotor indicated generally at 80, the solenoid packs indicated generally at 82 and the reservoir and pumps indicated generally at 84 are removably mounted. Casing 74 is provided with upstanding lugs 86 forming a slot between them. A lug 83 secured to the engine nose is located between upstanding lugs 86 when the propeller is assembled on an engine so that lug 88, while permitting relative axial and radial movement of casing 74 with respect to the engine nose, will 74 about the propeller axis 26.

prevent rotation of easing. If desired, some resilient.

material such as rubber may be inserted between lugs 86 and 88 to provide a more resilient connection. The control mechanism includes a governor 76 having the usual speeder spring 77 which may be adjusted by any suitable means such as manually by a pulley or as shown in Figure 2, by an electric motor 90. The usualflyweights, not shown, which are balanced against the speeder spring actuate governor valve. 92 to control the flow of fluid to and from servomotor 80. Hydraulic fluid which is carried in a reservoir 94 is pumped therefrom and placed under pressure by pump 96 driven by gear 62 by relative rotation of the propeller and casing 74. This pressure fluid is led through conduit 98 to the usual relief valve, not shown, and through conduit 100 to the governor valve 92. Governor valve 92 serves to selectively connect conduit 102 with pressure line 100 or with a drain to the reservoir 94. Conduit 102 is connected through normally open solenoid valve 104 with the chamber 106 of servomotor 80 to thereby move the servomotor and rack 108 under the influence either of pressure fluid 106 or the spring 110 at the opposite end of rack 108. Rack 108 meshes with gear 112 carried by an inner race 114 of a ball bearing indicated generally at 116. The outer race 118 of the ball bearing 116 is secured to control casing 74 by screws 121 as shown in Figure 5. In a manner which will be later described, movement of inner race 114 will move thrust plate 58 to effect the change in propeller itch.

p As described above, outer race 118 is secured to control casing 74. Outer race 118 is mounted on sleeve 42 to normally hold the control casing 74 in a fixed position with respect to sleeve 42 while permitting, under a selected condition, relative rotation of control casing 74 and sleeve 42. This mounting of control casing 74 on sleeve 42 is effected by means of small rolls 120 journalled on an axle 122 secured in a depending boss on the ring 118. As shown, there are four rollers 120 arranged around the outer race 118. If desired, more rollers might be added. Rollers 120 are given a rounded contour to fit a groove 124 in the outer surface of sleeve 42. These rollers are made a snug fit in the groove 124 so as to hold control casing 74 on sleeve 42 without any appreciable movement therebetween. Normally, casing 74 and sleeve 42 are held against relative rotation but under certain conditions such as feathering and unfeathering, which will be later described, it is possible to rotate sleeve 42 with respect to casing 74 at which time rollers 120 will roll around sleeve 42 in groove 124. By thus securing casing 74 against axial or radial movement with respect to sleeve 42, casing 74 is positioned with respect to hub extension 56 thus substantially limiting any relative axial movement between the control mechanism and the hub which would adversely affect the governing and the pitch control.

Inner race 114 carries rolls 126 which operate in axially extending grooves 128, in a sleeve 130, telescoped with race 114 and having an upstanding thrust plate 58 at one end thereof. Rolls 132, rotatably mounted on axles fixed on outer race 118, operate in angularly arranged grooves 134. The axles of rollers 132 are therefore held stationary with respect to housing 74 so that actuation of inner race 114 by rack 108 will, by means of roll 126, rotate sleeve 130. Rotation of sleeve 130 will cause axial movement thereof, as angularly arranged groove 134 passes fixed roller 132. Axial movement of sleeve 130 and thrust plate 58 carried thereby will axially move valve extension 56 to change the propeller pitch. The mechanism thus far described will, therefore, maintain constant speed of the propeller driving engine by the action of the governor valve 92 controlling the position of the rack 108 by means of the servomotor 106 and thus by controlling the position of thrust plate 58 and the inner part 54 of the valve 38 will adjust the propeller pitch to maintain a preselected speed.

A gear 136 on the inboard end of sleeve 42 meshes with a gear 138 which is operatively connected with the auxiliary motor 78. Fixed to gear 138 is a ratchet 140. A pawl 142 cooperates with ratchet of gear 138 to prevent rotation of gear 138 in one direction. Rotation of the propeller carried pumps about cam 40 tends to rotate sleeve 42 and gear 136 therewith. Rotation of sleeve 42, cam 40, and gear 136 in that direction, however, is prevented by gear 138 and the pawl and ratchet 140 and 142. Sleeve 42 is, therefore, fixed against rotation with the propeller.

Provision is made for disconnecting the propeller governor from the servomotor and manually controlling the position of the servomotor by manually controlling the flow of oil into and out of the servomotor. This manual control is provided by solenoid actuated valves 144 and 146 which are normally closed. In order to manually increase the propeller pitch, the solenoid of valve 104 is actuated to close valve 104 thereby blocking further control by the governor 76. If nothing further is done, oil will be locked in the servomotor and the propeller held at this manually selected pitch position. In order to increase the propeller pitch as in feathering or unreversing a solenoid is actuated to open valve 146 and allow oil to drain from chamber 106 through conduits 148, 150, and 152 to reservoir 94 as spring pushes the servomotor piston and rack to the left as viewed in Figure 2. Switches, not shown, may also be closed to actuate solenoid 154 to withdraw stop 156 and to actuate auxiliary motor 78. Actuation of auxiliary motor 78 will tend to rotate cam 40 and supply pressure fluid to the propeller as it slows down in approaching the feathering angle. To reduce the pitch as in reversing or unfeathering valves 104 and 146 remain closed and valve 144 may be opened, by manual actuation of a switch not shown, to introduce fluid under pressure from conduit 98 through conduit 148 to chamber 106 of the servomotor 80. This will move rack 108 to change the position of inner part of valve 38 and thus change the propeller pitch.

The actual arrangement of the electrical circuits and switches for actuating the several solenoids and the auxiliary motor have been omitted for purposes of simplicity and because it is believed that the invention can be readily understood without further description thereof. Reference may be had to application Serial No. 609,843, now Patent No. 2,619,182, however, for a further detailed description of these electrical circuits.

An auxiliary pump 158 is driven from gear 136 through gear 160. This auxiliary pump is normally stationary but is actuated whenever the auxiliary motor 78 is operated, to supply pressure to line 162 to thereby supply pressure fluid for the actuation of the servomotor whenever the propeller is not operating. Rotation of the propeller rotates gear 62 pinned to the inboard end of hub extension 20. A gear 164, Figure 2, meshes with gear 62 and is actuated thereby. Gear 164 is geared to the governor to drive the governor by rotation of the propeller. Gear 164 also drives pumps 96 for supplying pressure fluid to the governor. It will, therefore, be apparent that when the propeller stops rotating, it is necessary to have an auxiliary pump to supply pressure for operating the servomotor 80.

Control casing 74 terminates adjacent to the nose of engine 16 but its only connection with the engine is by means of lugs 86 and 88. If desired, a flexible boot or shield 166 may be placed over the joint between the engine and the control member to seal this opening.

It will be apparent that the above described structure provides a propeller-control unit which may be placed on or removed from the propeller shaft as a unit and in which the control mechanism is maintained stationary but is journalled on the propeller hub and held against axial movement relative to the propeller hub. It will also be apparent that the only connections necessary to connect the manual controls at the control station with the control unit of the propeller incident to installing the'propeller on a propeller shaft will be to locate lug 88 between lugs 86 and make the necessary electrical connections which may be made by the well known separable plug connections schematically indicated by the block 168. It will also be apparent that the propeller is a self-contained hydraulically actuated propeller having its own pumps and reservoirs and deriving its power for actuating the pumps by the rotation of the propeller except for the extra range operations where the power is derived from the airplane electrical system.

It is to be understood that the invention is not limited to the specific embodiment herein illustrated and described, but may be used in other ways without departure from its spirit as defined by the following claims.

I claim:

1. In combination, a propeller hub, including hydraulic pitch changing mechanism and a pump for supplying hydraulic fluid under pressure therefor, and having an axially extending projection concentric with the hub axis, a bearing sleeve rotatably supported on and concentric with said projection, means carried by said sleeve for actuating said pump by rotation of said propeller, a control housing supported on said sleeve, means preventing relative rotation of said housing and said sleeve, means restraining said housing against rotation, control mechanism carried by said housing including a reservoir, a pump, a servomotor and a control therefor, means carried by the propeller hub driving said last mentioned pump by rotation of said propeller hub to draw liquid from said reservoir and direct it to said servomotor control, and means operatively connecting said servomotor with said hydraulic pitch changing mechanism.

2. A unitary propeller control assembly comprising a propeller unit including a hub, blades and hydraulic pitch changing mechanism rotatable as a unit, a stationary control unit including a housing supporting a reservoir, a pump, and governor mechanism, means rotatably supporting said stationary control unit on said hub comprising an elongated sleeve rotatably supported on bearings on, and concentric with the axis of, said hub and means supporting said control unit on said sleeve, and axially positioning said control unit with respect to said sleeve, means for preventing rotation of said control unit and said sleeve with said propeller and means operatively connecting said governor mechanism with said hydraulic pitch changing mechanism.

3. In combination with a controllable pitch propeller having hydraulically actuated pitch changing mechanism and a support rotatable with said propeller, a stationary control unit comprising, a casing, hydraulic control mechanism supported on said casing and operatively connected with said hydraulic pitch changing mechanism, a bearing rotatably supporting said casing on said support, means permanently restraining said casing against rotation with said propeller, and means actuated by relative rotation of said support and said casing for supplying hydraulic fluid under pressure to said hydraulic control mechanism and said hydraulically actuated pitch changing mechanism.

4. A device as claimed in claim 2 in which the hydraulic pitch changing mechanism includes an entire hydraulic motor and means for conducting operating fluid to and from said motor.

5. A device as claimed in claim 4 in which the hydraulic motor has relatively movable parts, one of which is connected to the propeller blades and the other of which is fixed to the hub.

6. A device as claimed in claim 3 in which the hydraulically actuated pitch changing mechanism includes a hydraulic motor and a pump for supplying pressure fluid to said motor rotatable with said propeller and in which the means actuated by relative rotation of said support and casing includes said pump.

References Cited in the file of this patent UNITED STATES PATENTS 2,364,672 Stevenson Dec. 12, 1944' 2,467,964 Carson et a1 Apr. 19, 1949 2,476,638 Stuart III et al July 19, 1949 2,640,555 Cushman June 2, 1953 FOREIGN PATENTS 407,697 Italy October 1946 580,923 Great Britain Sept. 26, 1946

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