US 5,795,524 AGranted

Process for producing composite tubular parts

OwnerRobert J. Basso, Jr., Wayne E. Hogarthinventors

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Abstract

A mandrel is fitted with a molded sleeve of low-temperature alloy for forming a rigid bulge along the surface of the mandrel. The sleeve is shaped to define the internal surface of the shell at the bulge. After the mandrel has been so modified with the low-temperature alloy sleeve, it is wrapped with composite cloth containing any thermosetting resin. These resins heat to a known temperature, and permanently set when cured at the set temperature. The curing temperature of the prepreg cloth composite material is lower than the melting point of the low temperature alloy. After curing, the temperature in the curing oven is raised above the cure temperature until it reaches the melting point of the low-temperature alloy, and the alloy liquifies and drains out the drain passageways provided in the mandrel without melting the thermoset resin binder in the fiber cloth as well as leaving the bulge formed by the composite cloth in the shell without obstructing the removal of the mandrel. The resulting composite tubular shaft is thus provided with a bulge of increased diameter. The shafts may be tapered on the external surface or they may have a varied internal diameter.

Claims24

Dependent claims

A method of producing a tubular member having an internal diameter of at least a first magnitude and a region of said member having an internal diameter of a second magnitude comprising,

providing an elongated mandrel, having an end and an external surface,
surrounding at least a portion of said external surface with a mold having an interior surface diameter greater than the diameter of at least a portion of said external surface of said mandrel,
pouring a liquid moldable material capable of setting to a rigid condition into said mold to surround said portion of said external surface of said mandrel,
setting said moldable material to form a molded material in the shape of a rigid solid bulge on said at least a portion of said external surface of said mandrel,
removing said mold from said mandrel,
wrapping said mandrel including said bulge to form at least one lamina of a composite material consisting of a thermosetting resin and reinforcing fibers,
covering said composite material with a shrink wrap,
curing said thermosetting resin in said composite material by applying heat to said mandrel and said composite material to form said tubular member,
removing said molded material from said mandrel,
removing said mandrel from said tubular member, and
removing said shrink wrap after said curing step whereby said tubular member is produced.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/825,361Filed 28 Mar 1997
Granted: 18 Aug 1998
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

B29C 43/18
Of articles of definite length, i.e. discrete articles: incorporating preformed parts or layers, e.g. compression moulding around inserts or for…
B29C 33/52
With means for, or specially constructed to facilitate, the removal of articles, e.g. of undercut articles: soluble or fusible
B29C 53/824
Mandrels especially adapted for winding and joining: collapsible, e.g. elastic or inflatable; with removable parts, e.g. for regular shaped,…
B29C 70/462
Using matched moulds, e.g. for deforming sheet moulding compounds [SMC] or prepregs: moulding structures having an axis of symmetry or at least…