A fitting for the attachment of struts, tension members, etc., to spars or like structural members of the type comprising a boom wholly or partly of circular or polygonal cross section and with its edges lying wholly or partly on a circular are, is adapted to be rotated about the axis of the boom and to be fixed in any position within a given range to suit the inclination of the struts, tension members and the like. As applied to a spar comprising a circular boom a, Fig. 1, joined to another boom by a web a1 the fitting comprises a U‐shaped piece b which fits closely to the boom over an are of 180 deg. and is extended downward by parallel arms b1, b2 to form seatings b3, b4 for a iixing bolt c. The side edges of the fitting converge as shown in Fig. 2. Integral lugs d1, d2 are formed with their sides parallel to a radius of the boom and serve for attachment of a strut. Bolt c is passed through a sleeve g of the type described in Specification 352,767 and serves to secure link plates f1, f2, connected by a yoke piece f3 to which a tension member f is attached. The hole for bolt c is formed after the fitting has been assembled and adjusted to correct alignment with the strut and tension member. A similar fitting is described for a polygonal boom, the bolt c being located perpendicular to a diametrally opposed pair of polygonal boom faces. If the lines of force of strut and tension members are not at right‐angles to the bolt c the fitting may be aligned with the strut and the tension member offset on the yoke f3 the links 1, f2 being then made stiffcr. The tension members may be attached to bolt c2 securing a strut c or to bolts in similar lugs. The bolt c in this case passes through a compression member i such as is shown in Fig. 5, and which may extend for some distance along the boom. In a further modification the fitting a embraces the boom over a greater are than 180 deg. and is therefore made in two halves with a division between the lugs d1, d2. In a still further modification, Fig. 5, the fitting b is similarly shaped to the foregoing but is of sufficient internal diameter to slip over the boom on which it is located by shaped packing pieces h1, h2 and by bolt c. Bracing members may be attached to the boom by angle brackets having a part j fixed to the outer side of the fitting b and having a radially extending arm j1 to which a member such as k is fixed.
(1933), "Month in the Patent Office: A Selection of the More Important Aircraft and Engine Specifications Published Recently", Aircraft Engineering and Aerospace Technology, Vol. 5 No. 4, pp. 96-96. https://doi.org/10.1108/eb029675
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