US1501606A - Metal air propeller and the like - Google Patents

Description

H. LEITNER METAL AIR PROPELLER AND THE LIKE Filed Jan. 21, 192? Inventor Patented July 15, 1924.

- UNITED STATES PATENT OFFICE.

.HENBY LEITNER, OF LONDON, ENGLAND.

IETAL AIR PROPELLER AND THE LIKE.

Application filed January 21, 1922. Serial No. 580,845.

tageously detachable from the propeller hub and ad ustable therein for variations of itch and consequentl vary from an aerooil cross section in the body to a circular cross section at the root.

In carrying out the invention, the blade is made from two sections of sheet metal folded to form the edges of the blade, the said two sections being joined by a mechanical longitudinal seam extending along each side of the blade intermediate of the two folded ed es.

n a suitable arrangement for carrying out the invention, where the blade is made in two parts, I press or shape each blade so that part of the face and back thereof form one part of the blade lon itudinally with the edge of the blade formed by the bend of the metal between the face and back, including the laminations. This art may be, for example, that of the leading edge .of the blade, the other part being that of the trailing edge. The two portions having the bent edges and which will have the appearance of long curved troughs are then oined along the central or joint line either by lapping the edges of the sheets and riveting, or by a riveted metal strip which may be pressed up from the inside between the longitudinal dividing line, thus adding to the stillness and forming a sort of spar. Or what is known as a tinsmiths joint may be-used, that is to say, a strip of metal is bent at the edges completel round its own thickness and engages wit a similarly bent edge on the adacent edges of the blades and then both are pressed together and the central portion of the stripl is pressed into the dividing line between t e said two connected parts of the blades thus also forming a spar and stifiening; the clamped and compressed edges ma be further riveted, if desired, or blunt unc marks made therein to further 100 the joint; the foregoing methods of fixation are mentioned by way of example only as any other known method to secure the two part blades together may be employed.

As an alternative construction the blade instead of beinglin two parts may consist of one part only, is e back or face being shaped so that the edges of the blade are bent and prolonged to form either the back or the ace longitudinally, as the case may be, the

two meetin edges being joined together as described a ove.

To enable the invention to be fully under-v stood, I will describe it by reference to the accompanying drawing, in which Fi re 1 is an elevation of a hollow sheet meta propeller blade of the type having a cylindrical stem or root designed to turn in a bearing in the propeller hub for varyin the pitch, the said b ade being constructed in accordance with the invention.

Figures 2 and 3 are, respectively, sections on the lines 22, and 33, Figure 1, but drawn to a larger scale.

Figs. 4 and 5 are sections illustratin modifications of the 'oints in the back an front of the blade illustrated in Figures 2 and 3 respectively.

Fi 6 and 7 are similar views to Figures 4 an 5, illustrating further modifications.

Fi 8 is a modification of the joint shown in F1 re 7.

Re erring to Figures 1 to 3, a, b are the two parts of the propeller blade and o, d are the respective bends therein constituting the leading and trailing edges of the blade, each of the said two parts having a somewhat trou hlike form with their meeting edges over apping at about the centre of the blade and being secured by rivets e, or they may be securedby other means. Figure 2 is a section through the top of the blade where only one lamina is employed, whilst Fi ure 3 is a section nearer the root of the b ade where, say, two additional laminae are used, the overla ping joint being arranged as indicated, w ereas, where all the laminae enter the cylindrical casing f-forming the stem, the r1vets 6 may also pass through the said casing.

Instead of the overlapping joints described with reference to Figures 1 to 3 the edges of the parts a and b may butt together as indicated in Figures 4 and 5, the joints being covered by metal strips 9 secured to the said parts a and b by rivets It Or other means than rivets ma be employed.

Figures 6, 7 and 8 s 0w different forms of folded or tinsmiths joints for uniting the 5 edges of the parts a and b, that illustrated in Figure 6 showing the edges of the said arts folded together, the inner laminm in igure 7 being riveted to the said jointed outer lamina b rivets 2'. Figure 8 shows a 10 metal vstri 7' mtermediate of the adjacent edges of t e parts a and b and having the edges connected thereto by folded or tinsmiths joints.

Claim:

A screw propeller of the kind described, formed from two sections of sheet metal folded to form the edges of the blade, the said two sections being joined by a longitudinal mechanical seam extending along each side of the blade.

HENRY LEITNER.

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