US2925131A

US2925131A - Controllable pitch propeller

Info

Publication number: US2925131A
Application number: US779383A
Authority: US
Inventors: Richard B Willi
Original assignee: Baldwin Lima Hamilton Corp
Current assignee: Baldwin Lima Hamilton Corp
Priority date: 1958-12-10
Filing date: 1958-12-10
Publication date: 1960-02-16
Anticipated expiration: 1977-02-16

Description

Feb. 16, 1960 R. B. WlLLl CONTROLLABLE PITCH PROPELLER 4 Sheets-Sheet 1 W4 "I. 2 z? Filed Dec. 10. 1958 INVENTOR. RICHARD B. W] LLJ ATTORNEY R. B. WlLLl CONTROLLABLE PITCH PROPELLER Feb. 16, 1960 4 Sheets-Sheet 2 Filed Dec. 10, 1958 -Feb. 16, 1960 R. B. WILLI ,925

CONTROLLABLE PITCH PROPELLER Filed Dec. 10. 1958 4 Sheets-Sheet 3 1 INVENTOR.

RICHARD B. WILLI ATTORNEY Feb. 16, 1960 R. B. wu

CONTROLLABLE PITCH PROPELLER 4 Sheets-Sheet 4 Filed Dec. 10, 1958 #IIIMIIII HU 1 IIIIQ HH Ill,

INVENTOR. RICHARD B. WILL! ATTORNEY 2,925,131 CONTROLLABLE PITCH PROPELLER Richard B. Willi, Norristown, Pa., assignor to Baldwin- Lima-Hamilton Corporation, a corporation of Pennsylvania This invention relates to means for adjusting the pitch 'of adjustable blade propellers of the type in which each blade utilizes a set of two crank pins to which power means is so connected as to rotate each blade with equalized operating forces on the crank pins.

Such a mechanism is shown in my co-pending application Serial No. 516,428, filed June 20, 1955, and is so constructed and arranged as to obtain complete independent equalization of the adjusting forces acting on each blade. While the mechanism disclosed in said application has certain advantages which are desirable under many conditions of operations, yet it involves certain complications that add cost to the manufacture and possibly to the maintenance, as Well as requiring space for housing the additional complications. My present invention is an improvement over the invention of my said co-pending application.

' It is an object of my invention to provide an improved power operated mechanism for adjusting the pitch of propeller blades, that will insure not only independent equalized operating forces on the crank pins of the individual blades but at the same time will accomplish this with a relatively simplified arrangement of parts that is highly effective in minimizing the cost of manufacture and maintenance, as well as providing greater compactness.

Further objects and advantages will be more apparent to those skilled in the art from the following description of the accompanying drawings in which:

Fig. l is a longitudinal sectional view of my improved I mechanism taken substantially on the line 11, Fig. 2;

Fig. 2 is a transverse section taken substantially on the line 22 of Fig. 1;

Fig. 3 is a transverse section taken substantially on the line 33 of Fig. 1;

Fig. 4 is a perspective of the combined servo-motor and main crosshead, and of the auxiliary crossheads; and

Fig. 5 is a side elevation of Fig. 4 together with showing the control valve housing.

In the particular embodiment of the invention disclosed herein for the purpose of illustrating one particular form thereof, among possible others, I have shown a usual propeller shaft 1 to which a propeller hub 2 is secured by bolts 3. This hub has any desired number of radial propeller blades 4, specifically shown as four in number, broken off for simplicity of illustration. Each blade has a base 5 suitably journalled in hub recesses which terminate in an inward radial flange 6 to which the blade base is secured by a flanged nut 7 threadedly secured at 8 to a short extension of the base. Suitable means may be employed to angularly lock the threads 8 so that the nut 7 and base 5 are a single rotatable unit. To rotate the blades there is provided a main crosshead 16 and auxiliary crossheads 18. To connect the propeller blades to these crossheads each base nut 7 has two crank pins 10 and 11, Fig. 2, respectively journalled in

slide blocks

12 and 13, Figs. 2 and 5. Only one blade and its crank United Stews Paeiito mounted on piston rods 23.

pin operating relationship to the main and auxiliary crossheads and to a servo-motor mechanism will be described inasmuch as the remaining blades employ similar operating elements which are given the same reference numbers. The slide block 12 is disposed in a guideway 14 formed in the generally flat face of the main crosshead 16, there being four such sides corresponding to the four propeller blades. The other slide block 13 is guided in a guideway 17 formed in the auxiliary crosshead 18. This crosshead is slidably guided by the main crosshead in a longitudinally extending guideway 19, Fig. 4, having preferably a semicircular inner surface 20 and a bevelled surface 21 at one of its outer edges near the corner of the flat surfaces 22 of the main crosshead. The slide blocks thus move in a crosswise direction substantially at right angles to the direction of movement of the main and auxiliary crossheads.

To move both the main and auxiliary crossheads in opposite longitudinal directions so as to impart rotation to the crank pins 10 and 11 I provide a servo-motor mechanism, contained entirely within the main crosshead, having multiple piston and cylinder elements one for each auxiliary crosshead. As shown in Figs. 1, 3, and 5, four such cylinders 25, equally circumferentially spaced around the axis of the main crosshead 16, have pistons 27 These rod are provided with tail rods 29, preferably of the same diameter as rods28 to provide equal fluid pressure areas on opposite sides of the pistons 27. The piston rods and tail rods pass through suitable packing glads at both ends of the cylinder, the outer gland being formed in a suitable plate 30 secured to the end of the main crosshead. Each rod 28 is shouldered so as to be secured in its auxiliary crosshead 18 by a nut 31. The main crosshead is provided with a cylindrical portion 32, Fig. 4, guided in a cylindrical bore 33, Fig. l, which is formed in the forward end of propeller hub 2 which broadly includes a cone 34 secured to the main portion of the hub by cap screws 35.

The main crosshead has a guiding tail shaft 38 slidably supported by the propeller hub, specifically by being guided in the bore 39 of propeller shaft 1 to which the hub is connected. A valve stem 40 extends through the tail shaft 38 for connection to a spool valve 41 disposed within a valve housing 42 whereby fluid pressure, from a suitable source, may be supplied through a passage 43 thence through the valve ports to one or the other of

passages

44 or 45 to the ends of the cylinders 25. When fluid pressure is supplied to one of the ends of the cylinders through, say, passage 44, fluid is discharged from the other ends of the cylinders through passages 45 and thence through an annular discharge passage 46, or vice versa.

0perati0n.-ln operation fluid pressure is supplied, Fig. 1, through passage 43 and valve 41 to, say, passages 44 thereby exerting a pressure force in a right-hand direction on pistons 27 and on auxiliary crossheads 18 and in a left-hand direction on the cylinder head plate 30 tending to move the main crosshead 16 in a left-hand direction. This produces a turning moment on the crank pins disposed within the

slide blocks

12 and 13, Fig. 5, thus rotating the propeller blade connected thereto. As the blade rotates, the slide block 12 will move in a crosswise direction within the guideway 14 of the main crosshead and similarly the guide block 13 will move in the guideway 17 of the auxiliary crosshead 18 thereby allowing each crank pin to swing in arcs 48, Fig. 5, as the propeller blade turns.

Even though the main crosshead is common to each propeller blade yet each crank pin will have equalized operating forces exerted thereon because the auxiliary crossheads are capable of moving relative to and independently of each other without any loss of magnitude of fluid pressure force which is created from a common source of pressure transmitted through the axial supply passage 43. Hence any wear that might occur in one or more of the crank pins hearings will automatically be taken up regardless of whether or not wear has occurred in any of the other crank pins. This is accomplished in a servo-motor mechanism that has a high degree of simplicity and compactness and that lends itself to minimum maintenance as Well as reduced initial cost of manufacture.

' It will, of course, be understood that various changes in details of construction and arrangement of parts may be made by those skilled in the art without departing from the spirit of the invention as set forth in the appended claims.

I claim:

1. A propeller having a hub and angularly adjustable blades journalled therein, a pair of crank pins connected to each of said blades for angularly adjusting the same, a main crosshead connected to one crank pin of each blade, a plurality of auxiliary crossheads connected respectively to other crank pins of the blades, means for slidably guiding the main and auxiliary crossheads so that they move in opposite directions to impart rotation to the crank pins and thus angularly adjust the propeller blades, and power mechanism supported by the movable main crosshead and having connection therewith and with each of the auxiliary crossheads for simultaneously oppositely moving the main and auxiliary crosshead to eflect said angular blade adjustment.

2. A propeller having a hub and angularly adjustable blades journalled therein, a pair of crank pins connected to each of said blades for angularly adjusting the same,

a main crosshead connected to one crank .pin of each blade, 7

a plurality of auxiliary crossheads connected respectively to other crank pins of the blades, means for slidably guiding the main and auxiliary crossheads so that they move in opposite directions to impart rotation to the crank pins and thus angularly adjust the propeller blades, a plurality of cylinders disposed in said main movable crosshead for movement therewith, there being one such cylinder for each auxiliary crosshead, pistons in each of said cylinders connected respectively to said auxiliary crossheads, and means for supplying operating fluid to similar ends of said cylinders and discharging fluid from the opposite ends thereof, whereby the action and reaction fluid forces within the cylinders produces an operating force in one direction on the main crosshead and in the opposite direction onthe auxiliary crossheads thereby to effect angular adjustment of the propeller blades.

' 3. The combination set forth in claim 2 further characterized in that the means for'slidably guiding the auxiliary crosshead includes guideways therefor disposed on said main crosshead.

4. The combination set forth in claim 2 further characterized in that the means for slidably guiding the auxiliary crossheads includes guideways therefor disposed on said main crosshead, cross-guideways formed in the auxiliary and main crossheads extending in a direction substantially at right angles to the direction of movement of the crosshead, slide blocks disposed in each of said cross-guideways, the crank pins having a joumalled relation between the propeller blades and slide blocks so that movement of the main and auxiliary crossheads in opposite directions together with cross movement of the slide blocks will transmit movement from the slide blocks to the propeller.

5. The combination set forth in claim 2 further characterized in that the means for slidably supporting the main crosshead includes a cylindrical portion at one end thereof slidably supported in the propeller hub, and the means for slidably guiding the auxiliary crossheads includes guideways therefor disposed on said main crosshead, crossguideways formed in the auxiliary and main crossheads and extending in a direction substantially at right angles to the direction of movement of the crosshead, slide blocks disposed in each of said cross-guideways, the crank pins having a journalled relation between the propeller blades and slide blocks so that movement of the main and auxiliary crossheads in opposite directions together with cross movement of the slide blocks will transmit movement from the slide blocks to the propeller blades, a tail shaft at the other end of the main crosshead, and mean for slidably supporting suchtail r0 7 V i 6. The combination set forth in claim 2 further characterized in that the main crosshead has an axial bore extending in the direction 'of the movement of the crossheads, a fiuid supply control valve supported on the end of the main crosshead, and a valve stem extending through said axial bore for controlling said valve.

References Cited in the file of this patent UNITED STATES PATENTS 2,355,039 Eves Aug. 1, 1944 2,686,569 Bruce Aug. 17, 1954 2,794,508 Pehrsson June 4, 1957