US 3,967,996 AGranted

Method of manufacture of hollow pieces

OwnerNikolai Ilich Kamov, Nikolai Nikolaevich Priorov +9inventors

InventorsNikolai Ilich Kamov, Nikolai Nikolaevich Priorov, Anatoly Fedorovich Kovalev, Mark Alexandrovich Kupfer, Alexandr Georgievich Satarov, Iosif Shulimovich Sherman, Anatoly Filippovich Vakulenko, Igor Ivanovich Kovyryalkin, Stanislav Ivanovich Stetsenko, Vladimir Borisovich Golstman, Konstantin Nikolaevich Guskov

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Abstract

A method of manufacturing hollow pieces comprising the steps of forming a blank of single sheets each having a layer of gluing substance applied thereto; placing the blank onto an appropriate mandrel and subjecting it to a preliminary compression so as to impart to the blank a stiffness and to shape it into an unclosed profile as required for subsequent steps. Then the blank ends are brought together so as to define a cavity accommodating an elastic bag. The resulting blank is placed into a mould, and pressure is fed into the elastic bag to perform a final pressing. The above-described method is preferably used to manufacture helicopter rotor blades of glass plastic, which have variable cross-sectional shape over their length and exhibit higher strength and longer service life as compared with metal blades.

Claims12

Dependent claims

A method of manufacturing hollow blades and hollow blade spars of aircraft rotors having a variable cross-sectional shape, comprising the steps of:

making a composite blank by first assembling each component part thereof from separate flexible flat sheets cut from an adhesive-covered cloth of material which sheets are placed one onto another on a rigid mandrel having an outer surface corresponding with the inner surface of the blade;
subjecting each of the component parts assembled of separate sheets and lying on the rigid mandrel to a preliminary compression which consists of applying pressure and heat to the sheets to cause agglutination of the sheets and forming a component part of a blank having an unclosed profile and a rigidity sufficient for subsequent steps;
assembling the component parts so as to form a cavity of a closed profile;
placing an elastic bag into the cavity;
placing the blank assembled of its component parts and with the elastic bag in its cavity into a mold whose inner surface corresponds with the outer surface of the blade;
and performing final pressing by supplying pressure into the elastic bag and heating the blank whereby the blade of a specified shape is produced.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 05/512,307Filed 4 Oct 1974 · continuation
Priority: 14 May 1973
Granted: 6 Jul 1976
Term ends: Not estimatedThe source records don’t support an estimate.

Classification20 codes

B29D 99/0028
Producing blades or the like, e.g. blades for turbines, propellers, or wings: hollow blades
B23P 15/04
Making specific metal objects by operations not covered by a single other subclass or a group in this subclass: turbine or like blades from…
B29B 15/125
With a matrix in liquid form, e.g. as melt, solution or latex: by dipping
B29C 49/44
Component parts, details or accessories; Auxiliary operations: for applying pressure through the walls of an inflated bag