US2392341A - Variable pitch propeller - Google Patents

Description

Jan. 8, 1946.

W. W. SQUIER VARIABLE PITCH PROPELLER Filed Sept. 10, 1942 5 Sheets-Sheet l Jan. 8, 1946. w. w. SQUI ER I VARIABLE PITCH PROPELLER Filed Sept. 10, 1942 3 Sheets-Sheet 2 W. W. SQUIER VARIABLE PITCH PROPELLER s Sheets-Sheet s Filed Sept. 10, 1942 awnings Jan. 8, 1946;

ill.

Patented Jan. 8, 1946 VARIABLE PITCH PROPELLER William W. Squier, Flint, Mich. Application September 10, 1942, Serial No; 457,849

8 Claims.

My invention relates to propellers. particularly I for aircraft, and its principal object is to provide simple and reliable means for changing the pitch of the propeller blades.

A primary feature of the invention consists inv providing a variable pitch propeller with a plurality of blade elements rotatably mounted. in the hub thereof and with reciprocal means interposed between the inner ends of the blade elements for cooperating with laterally spaced portions of the latter for simultaneously rotating them in opposite directions.

Another feature of the invention consists in providing the inner ,ends' of each of the rotatable blade elements of the propeller with a pair of studs and in movably mounting a plate-like member intermediate the inner ends of the blade elements for simultaneously rotating them in opposite directions, opposite edges of the plate member having angularly related cam surfaces for respectively engaging the studs on the blade elements.

A further feature of the invention consists in providing pressure responsive means for moving the pitch changing member of the device in a direction for increasing the pitch of the blade elements and in providing adjustable spring means for moving the pitch changing member in the opposite direction to decrease the Ditch of the blade elements.

A still further feature of the invention consists in providing'diaphragm means connected to the pitch changing member and subject to the pressure of the lubricating oil in the internal combustion engine to which the propeller is attached for moving the pitch changing member in a direction to increase the pitch of the blade elements and in also providing adjustable spring means normally resisting movement of the pitch changing member in a direction to increase the pitch.

Other and more specific features of the invention, residing in advantageous forms, combinations and relations of parts, will hereinafter appear and be pointed out in the claims.

In the drawings Figure 1 is a sectional view of the propeller and the adjacent portion of an internal combustion engine to which the propeller is attached, the view being taken through the central portion of the hub of the propeller in a plane-parallel with the axis of rotation of the propeller.

Figure 2 is another view partly in section and partly in elevation of the propeller and the adjacent portion of the engine to which the probeing in a plane parallel with the axis of rotation of the propeller and at right angles to the view shown in Figural. I

Figure 3 is a front view of the propeller. Referring more particularly to the drawings.

, the propeller includes a hub I which consists of a housing preferably formed in two parts, an inner part '2 and anouter part 3. These two parts of the housing are bolted together by bolts 4 which extend through registering apertures in laterally projecting companion flanges .5 and 6 with which the two parts are respectively provided. The base of the inner part 2 of the hub or housing is formed with a circular flange I by which the propeller may be rigidly connected by bolts 8 to a similarly shaped flange 8 on the outer end of a crank shaft Ill of an internal combustion engine ll.

Rotatably mounted in the hub are propeller blades I! which may either be directly journaled in the hub if they are made of metal, or mounted in holding clamps I3 which are rotatably journaled in the hub. To facilitate assembly, each of the blade clamps is made in two preferably identical parts, the inner ends of which may be held together by a pair of rings I4 and i5, respectively, while the outer ends are preferably held together by bolts l8 whichpass through apertured lugs l'l.

. While the complementary faces of the two halves of each clamp engage each other adjacent their inner ends, they are spaced apart as indicated at l8 adjacent their outer ends so that the innerv end of the propeller blade which is mounted therein may be very tightly clamped.

In addition to being encircled by the rings I4 and IS, the two halve of each blade holding clamp are also encircled by a. double race ball bearing unit consisting of an outer race 20 mounted within a groove formed in the inner surface of the hub and an inner race 2| which bears against a peripheral shoulder l9 formed on the inner end of the blade clamp. While the two .rings ll and I5 tightly fit the blade clamps and are spaced slightly from adjacent portions of-the hub, the rings [5 are suitably formed to receive packing material 22 to-prevent dust from getting into the bearin s and to retain the lubricant.

Projecting inwardly from the butt end of each blade clamp are a pair of studs, the studson the clamp of the propeller blade shown in full lines and designated A in Figure 1 being numbered 23 and 24, respectively, and the two studs of the. clamp for the blade shown in dot and dash lines and designated by the letter B in Figure 1 being numbered 25 and 26, respectively. Interposed peller is attached, the sectional part of the view 66 between the inner ends of the blade clamps r elements is a reciprocal member 21 -whose side edges are each formed with a pair of cam surfaces 28 for cooperating with the studs on the clamps to simultaneously rotate the clamps and blades in opp ite directions. The studs of one blade clamp respectively engage the cam surfaces onone edge of the reciprocal member while the studs on the other clamp respectively engage the cam surfaces on the opposite edge of the reciprocal member. The cam surfaces on each edge of member 21 are disposed at a 90? angle to each other and each forms an equal angle with the direction in which the member is capable of being moved. With the cam surfaces arranged in this manner, both studs of each of the blade holding clamps will constantly engage the respectively cooperating cam surfaces of the reciprocal member in all positions of adjustment the latter may assume. To compensate for any wear which may occur between the studs and the cam surfaces,

rocal member by a pair of plates 38 which are rigidly clamped to opposite faces of the diaphragm by nuts 21 which are threaded upon the guide rod II.

So that the diaphragm will besubject to the pressure of the lubricating system of the engine, the forward portion of the engine crank case is provided with a passage 38 leading to a circular groove 39 surrounding the crank shaft III. Fitted withinthe end of the crank shaft which is usually 1 passage 38 and the circular groove 39 of the crank the studs may be advantageously provided with a rotatable sleeve 29 which may be easily removed and replaced to take up any looseness between the parts.

To guide the member 21 in its reciprocating movement, it is provided with oppositely projecting rod- like elements 30 and 3|, respectively, which extend at an oblique angle to the cam surfaces 28. The guide rod 30 extends into an opening which communicates with. an annular boss 32 formed on the outer part 3 of the hub, while the guide rod 3| extends into an aperture which communicates with an enlargedrecess 34 in the base of the inner part 2 of the hub.

With the reciprocal member being thus restrained from any movement except a rectilinear one in a direction with which each of the cam surfaces 28 form equal angles, it will be perceived that, when the member moves upwardly as viewed in Figure l, studs 24 and 26 of blades A and B, respectively are forced apart and the blades are thus caused to simultaneously rotate equal amounts in opposite directions to increase their pitch. When the reciprocal member and studs have moved sufllciently'to assume the dotted line position indicated in Figure 1, the blades A and B will respectively assume the positions designated by the letters A and B. To decrease the pitch of the blades, the reciprocal member 21 is moved downwardly from the dotted line position indicated in Figure 1 and by cooperating with studs 28 and causes the blades to rotate in opposite directions toward the positions respectively designated by the letters A and B. It will, of course, be appreciated that forces transmitted from the two blade clamps to thereciprocal member will not tend to move the latter because they act in opposite directions, are of equal magnitude and are respectively opposed by forces. of the.

the lubricating system of the internal combustion.

engine to which the propeller is attached is preferably employed. This means consists of the diaphragm 35 which is made of any suitable material such, for example, as synthetic rubber.- The peripheral edges of the diaphragm are firmly clamped between the coacting faces of the inner part 2 of the hub I and the flange 9 on the crank shaft i0, while the central portion of the -diaphragm is connected to guide rod 3! of the recipcase, enters through openings 4| and 42 into the forward end of the crank shaft where it presses against the diaphragm 35. The crank case is fitted with suitable seals 43 on both sides of the circular groove 39 to prevent leakage of oil around the crank shaft.

' The diaphragm is of sufficient area that the engine oil pressure will cause the reciprocal member 21 to move upwardly-as viewed in Figure 1 against the tension of aspring 44 mounted withmits setting the spring load to the maximum amount that the engine oil pressure can overcome thereby holding the pitch in either the maximum or minimum pitch ,position. High spring and oil pressures quickly overcome friction and aerodynamicv forces. When engine is not running, the spring will hold blades in their low pitch position. Since high pitch is only needed at cruising or top speeds, engine oil pressure is always available to change the pitch at the will of the pilot by simply operating the valve 48. Closing of this valve would be arranged to release the oil pressure under the diaphragm allowing the spring to move the blades back to the. low pitch position. The tension of the spring is normally such that when the e the oil pressure thusduced to a minimum, the reciprocal member 21 will return to the full line position shown in Figure 1 to move the blades back into "low 'pitch and thus produce a brake eflect.

Passage of oil from the lubricating system of the engine to the diaphragm 25. may be controlled by any suitable valve mechanism, such, for example, as a manually controlled valve 48 or the well known governor controlled type of valve which would valve in or release oil from the space under the diaphragm so as to provide a constant speed control.

From the foregoing, it will be perceived that the propeller blade angle changing device is of unusually simple design involving but a single moving part, is economical to build and is. of ex- 'tremely rugged construction. The hydraulic control; mechanism is particularly advantageous as it has no piston rings or packing within the'propeller which might leak, and no oil is in the outer ine throttle is closed and in the device without departing from the spirit oi the invention as defined in the appended claims.

What I claim is: 1. A variable pitch propeller comprising a hub, a plurality of blade elements rotatably mounted in said hub, the inner end of each of said blade elements having laterally spaced rigid portions, a reciprocal plate-like member interposed between the inner ends of said blade elements for cooperating with said portions to cause the blade elements to simultaneously rotate in opposite directions, each of said portions being constantly in direct engagement with said member in all positions of adjustment it may assume and the portions of one of said blade elements acting on said member in opposition to the portions of the other blade element, rod-like means rigid with said plate-like member enabling it to be moved in a direction to increase the pitch ofthe blade elements, additional rod-like means rigid with said plate-like member to move it in the opposite direction to decrease the pitch of theblade ele'- ments. and adjustable spring means cooperable with said last named rod.

2. A variable pitch propeller comprising a hub. a plurality oi blade elements rotatably mounted in said hub, each of said element having a pair ofv studs projecting inwardly from its inner end. each of said studs comprising a portion rigid with its blade element and a sleeve encircling said portion, and areciprocal member for simultaneously rotating said blade elements in oppo-' site directions, said member having opposed cam surfaces interposed between the inner ends oi said blade elements, said cam surfaces being respectively cooperable with the studs on the different blade elements and each pair of said studs studs, each cam surface having angularly disposed portions constantly in direct engagement with the studs of each pair and each stud including a removable rotatable sleeve.

5. A variable pitch propeller comprising a hub, a plurality of' blade elements rotatably mounted in said hub, each of said blade elements being rigidly provided with a pair of studs projecting inwardly from its inner end, a rectilineally movable reciprocal plate-like member for simultaneously rotating said blade elements in opposite directions, said member having rigidly united cam surfaces respectively having pairs of angularly disposed portions, each one of the pairs of said angularly disposed portions of said member being in direct engagement with one of the pairs of said studs, and means rigid with said being constantly in direct engagement with its 00- operating cam surface in all positions of adjust: ment said member may assume the cam surfaces in engagement with the studs of the same blade element being arranged at 90 to, each other.

3. A variable pitch propeller comprising a hub, a plurality of blade elements rotatably mounted in said hub, each of said elements being rigidly provided with a pair of studs projecting from its inner end, and a reciprocal rigid member interposed between the inner ends oi said blade elements for cooperating with said studs to cause the elements to simultaneously rotate in opposite directions, said member being rigidly provided with opposed cam surfaces each of which has angularly disposed portions respectively in direct engagement with the studs of one of said blade elements whereby said blade elements are caused to rotate upon movement of said means in either direction.

4. A variable pitch propeller comprising a hub, a plurality of blade'elements rotatably mounted in said hub, each of said blade elements being rigidly provided with a pair of studs projecting inwardly from its inner end, and a reciprocal member for simultaneot ily rotatingsaid blade elements in opposite directions, said member being interposed between the inner ends of 881C! blade elements having opposed cam surfaces rigid therewith respectively engaging said pairs of cam surfaces for guiding said reciprocal member.

6. A variable pitch propeller comprising a, hub. a. plurality 01' bladeelements rotatably mounted in said hub, each of said blade elements being rigidly provided with a pair of studs projecting inwardly from its inner end, a reciprocal plate-' like member interposed between the inner ends oi said blade elements, said pairs of studs being respectively engageable with the opposite edges of said plate member and each edge of the plate having angularl related surfaces in direct engagement with the adjacent stud, and means rigid with said plate member and extending obliquely with respect to said cam surfaces for guiding said member.

7. A variable pitch propeller comprising a hub,

a plurality of'blade elements rotatably mounted in said hub, each of said blade elements being rigidly provided with a pair of studs projecting inwardly from its inner end, and a unitary reciprocal member for simultaneously rotating said blade elements in opposite directions, said member including a plate portion and elements pro- -jecting in opposite directions from said plate portion for guiding said member, opposite edge portions of said plate portion being respectively provided with pairs 01' angularly disposed cam surfaces in direct engagement with the studs oi the blade elements whereby said blade elements are caused to rotate in opposite directions upon rectilinear movement of said unitary member/ 8. A variable pitch propeller unit for attachment to the crank shaft of an internal combustion engine, said unit including a hub adapted to be secured to said crank shaft a plurality 0! blade elements rotatably mounted in said hub, movable means mounted in the mm between the inner ends of said blade elements for simultaneously rotating the latter in opposite directions, said means including a plate portion and oppositely extending guides, diaphragm meansconnccted to one of said guides subject to the,

WILLIAM W. SQUIER.

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