US2604952A - Reversible propeller - Google Patents

Description

July 29, 1952 R. E. BELL REVERSIBLE PROPELLER Filed Sept. 20, 1947 IIIIIIIII) IN VENTOR ROSS EARL BELL.

AT TORNEV Patented July 29, 1952 REYEYRSIBLE mbaaa. j

' p Ross EarbBell,VancouyerfBritish Columbia, Canada-* Amati September 9 t1$aiflNW309} 1 IGlaim. (Oldie-13 311 V My invention relates to improvements in optimum efficiency from a reversible propeller when operating in forward and reverse directions and to prevent drag in these directions and also when the propeller is operating in neutral and in consequence nearly all of such propellers are less eflicient in operation in every one of their running positions than the conventional solid propeller.

In view of the above objection, the present invention is designed to be most efiectively stream lined and so constructed generally that its efficiency is equal to the conventional solid propeller when set to operate in a forward direction and to allow the loss of efiiciency which is now unavoidable in reversible propellers, to be taken when said propeller is set to run in reverse direction, or when high efficiency is not essential.

Referring to the drawings:

Fig. 1 is a front elevational view of the invention.

Figs. 2, 3 and 4 are transverse sectional views of the blades taken on the lines 2-2; 3-3 and 4-4 of Figure 1 respectively.

Fig. 5 is a sectional detail view of the pivotal mounting of each blade.

Fig. 6 is a sectional view of the propeller hub.

Figs. 7, 8 and 9 are side elevational views of the propeller in forward, neutral and reverse positions respectively.

In the drawings like characters of reference indicate corresponding parts in each figure.

The numeral N indicates generally a propeller shaft upon which a hub I2 is secured. The hub I2 is provided with a cylindrical portion I3 and a tapering trailing end I4. Extending radially from the portion I3 of the hub I2 are pivot pins I5 having a cylindrical bearing portion I6, a thread I1 and a reduced stem portion l8, and on each of the pivot pins I5 a propeller blade 2| is fitted.

Each blade 20 has an inner face 2| which lies in a plane substantially touching the outer peripheral wall of the hub I2 and is drilled outwardly from said inner face with a hole 23 having an inner bore 24 and a counterbore 25 and a thread 26 between said bores which is adapted to freely receive the thread I'I. Each blade 2| is screwed onto its pivot pin I5 to prevent substantial endwise movement and to be rockingly supported on said pin with the cylindrical bearing portion journalled in the counterbore 25 of the hole 23 and the stem portion I8 journalled within the inner bore 24 of said pivot pin I5. Each blade is fitted with a bolt 21 which extends from its inner face and is disposed to the rear or toward the trailing edge of said blade. The blades are stream lined in cross section, as shown in Figures 2, 3 and 4, with their forward faces convexed transversely and their rear faces lying in substantially the plane of the chords of the 7 sections shown.

Slidably mounted upon the shaft II is a hub shell 30 having tangential wings 3|, each of which conform substantially to the rear part of the inner face 2| of the blade. The wings are slotted inwardly from their outer ends as at 32 to embrace the bolts 21. The hub shell 3| is fitted to a sleeve 34 which is iournalled in suitable bearings, not shown, and said sleeve surrounds the propeller shaft I I to rotate therewith.

Longitudinal slots 35 are formed in the hub shell 30 which straddle the pivot pins I5, so that when the said hub shell is moved rearwardly along the hub, the wings 3| through the bolts,

21. rock the blades 2| about the pivot pins I5 until said pivot pins are disposed adjacent the inner ends of the slots 35 and the wings 3| are directly aligned with the inner faces 2| of the blades. When the wings 3| are so disposed, viz, with their edges parallel to the edges of the faces 2|, the propeller is adjusted for forward driving and a minimumresistance to rotation is encountered from said wings because they are directly behind the said inner faces. As the sleeve 34 is moved forwardly the wings 3| are likewise forwardly moved, so that the forward edge of each of said wings will be exposed to side thrust from the water. The movement of the shell in a forward direction will first bring the forward and trailing edges into a plane parallel to the radial plane in which the pivot pins l5 are set, thus restraining them from exerting any thrust lengthwise of the shaft 2. A still further movement of the hub shell 3| in a forward direction will rock the blades to cause the propeller blades to exert a thrust in a rearward or reverse direction. In the last mentioned position, the side areas of the wings are exposed to their greatest extent and impose a resistance to rotation, but as speed and optimum propelling pivot pin.

thrust is not necessary in this direction the eiilciency loss is unimportant.

What I claim as my invention is:

A reversible propeller comprising a hub shell and a hub telescopically mounted therein, said hub having a plurality of radially extending pivot pins, a propeller blade swingingly mounted upon each of said pins, means on the hub shell for rocking the blades upon their pins in response to endwise movement between the hub shell and the hub, each of said pins having a bearing portion at its inner end and at its outer end and a threaded portion between said bearing portions, each of said blades being bored to form journals about the inner and outer bearing portions and having an internal thread between said journals to fit the thread of the pin, said thread forming the sole means for retaining each blade upon its aoss EARL BELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Number Name Date Bailey Apr. 16, 1878 Hain T Nov. 16, 1897 Patrick May 16, 1905 Roper Feb. 4, 1908 Gnaegy Apr. 21, 1908 Bowers Jan. 26, 1909 Esson Mar. 11, 1913 Iskols May 2, 1916 Bell Jan. 10, 1950 FOREIGN PATENTS Country Date France Mar. 17, 1931

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