US1947365A - Airplane propeller - Google Patents

Description

Feb. 13, 1934. J. E. THOMPSON AIRPLANE PROPELLER 2 Sheets-Sheet 1 Filed Nov. 25, 1931 Cllfoc "curd J. E. THOMPSON AIRPLANE PROPELLER 1 Feb, 13, 1934.

I 2 Sheets-Sheet 2 Filed Nov. 25, 1931 Patented Feb. 13, 1934 UNITED STATES PATENT orrlca Application November 25, 1931 Serial No. 577 323 1 Claim. (01. 170-163) This invention appertains to improvements in propellers, particularly the variable pitch type used for airplanes. The independent mounting of the propeller blades in such constructions presents a difiicult problem primarily due to the necessity to take care of the stresses on the blades from centrifugal action during rotation of the propeller. In this respect the present invention represents improvements over the construction of my previous Patent 1,332,528, dated March 2,

1920, and it has for its object to provide counterbalancing means for each blade by means of which the centrifugal stresses are eliminated.

and vibration reduced to a minimum.

Other and further objects and advantages of the invention will be hereinafter set forth and the novel features thereof defined by the appended claim.

In the drawings, v

Fig.1 is a front elevation of apropeller constructed in accordance with my invention, the housing for the mounting being shown in section;

Fig. 2 .is an enlarged view partly'in section;

Figs. 3, 4, 5 and 6 are sectional views on the 2 lines 3 -3, 4- 4,-55 and 6-6, respectively, of

Fig. .2. and

Fig. 7 is a detail view of a single blade unit. Like reference characters designate corresponding parts in the several figures of the draw- 30 ings.

Referring first to Fig.7 each blade comprises a blade proper 1, the shank of which is formed centrally with an enlargement or shoulder portion 2 and adjacent to thisportion are formed '35 worm teeth 3. At the end of the shank there is provided an integral counter-weight 4 so shaped as to extend about the shank of the companion blade with which it cooperates and with a view to the provision of maximum weight at the op- 40 posite side of the axis of rotation of the blade.

It will be understood of course that I do not desire to be confined to any particular shape of this counter-weight, this being a matter of adaptation of construction to give compactness and $5 proper balance.

As shown in'the other figures of the drawings,

, formed to receive the enlargement 2 of the propeller shanks, this shoulder construction preventing longitudinal displacement of the blades and materially strengthening the blade where the centrifugal stresses are greatest. The enlargement- 2 is suitably cut away at 2' to accommodate the propeller shaft 6 in its various positions.

Any desired means maybe employed for shifting or varying the pitch of the blades, such for example, as shown in my prior patent above mentioned. Preferably the worm shaft 8 extends intov the housing 5 for this purpose and its gear 9 meshes with the teeth 3 on the propeller blades, thus providing a single control for adjusting the pitch of the bladescorrespo'ndingly and materially reducing the number of parts required for accomplishing the desired result. It will be understood that-the rotation of the 30 blades will be limited by the contact of the wings of the weights 4 with the shank portions of the blades, as clearly shown in Fig. 6 of the drawings. As a further detail of construction a guard casing 10 surrounds the hub or shank portion of 5 the propeller device similar to the arrangement shownin my previous patent.

Having thus described my invention, what I claim asnew and desire to secure by Letters Patent is: A variable pitch propeller comprising a pair of blades, the shank portions of which are arranged in overlapping relation, a counter-balance weight connected to the end of each shank and having spaced wing portions coacting with the adjacent blade shank to limit the rotative movement thereof,.common means for connecting the shanks to the propeller shaft, and means for rotating the blades to vary the pitch of the same.

JOHN E. THOMPSON.

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