US 6,759,000 B2Granted

Method of making a filtering screen and support frame therefor

AssigneeUnited Wire Limited

InventorsGordon James Cook, Andrew Hughes, Arthur Robert Bailey, George Charles Hartnup, Dugald Stewart

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Abstract

A method of constructing a frame (10) for a filtering screen from a polymer material is described in which a wire frame reinforcement is wholly encapsulated during the frame moulding process so that two parallel spaced apart wires extend through each of the intersecting orthogonal ribs (14, 16) which define the open area of the frame (10) across which the wirecloths (158, 159) are stretched. The surfaces of the frame (10) in which the wirecloths (158, 159) are embedded are formed with ridges (22, 30, 32) and the crests of the latter extend to different heights. The crests are softened by heating during the manufacturing process and the wirecloths (158, 159) stretched over the frame (10) are forced into the softened crests after which the assembly is allowed to cool and cure. The frame (10) is re-usable by stripping wirecloths (158, 159) from the top of the frame (10) and fitting fresh wirecloths over the plastics material and heating the regions which are to encapsulate the fresh wirecloth.

Claims16

Dependent claims

A method of constructing a polymer support frame over which woven wire cloth is to be stretched and secured to form a sifting screen, the method comprising the steps of:locating in a mould tool a reinforcing wire frame assembly comprising two parallel stated apart arrays or reinforcing wires:

(a) closing the mould tool;
(b) injecting liquid polymer into the mould tool by injection moulding so as to wholly encapsulate the wire frame and to form an article having an open central region criss-crossed by intersecting orthogonal ribs bounded on all sides by a rigid flange, the article being such that each of said ribs includes two parallel spaced apart wires of said frame assembly;
(c) exerting an inward force an opposite faces of the wire frame assembly within the mould tool by fingers protruding inwardly from inside faces of the tool, said fingers being operable to engage the arrays when the tool closes, the fingers comprising inwardly projecting pegs which align with crossing points of wires in the upper and lower reinforcing matrices, to space the arrays from the corresponding upper and lower internal surfaces of the mould tool and ensure that the arrays are buried within the plastics material which is injected into the mould tool during the manufacturing process, and the ends of the pegs taper to an edge, or a point and wherein after the mould tool is opened the protruding pegs disengage from the struts leaving openings in the polymer, and the method further comprises the step of plugging the openings with plastics material or filler,
(d) permitting the polymer to cure;
and
(e) opening the tool;
and removing the article.

4 more elements

A method of constructing a polymer support frame over which woven wire clot is to be stretched and seemed to form a sifting screen, the method comprising the steps of:

(a) locating in a mould tool a reinforcing wire frame assembly comprising two parallel spaced apart arrays of reinforcing wires;
(b) closing the mould tool;
(c) injecting liquid polymer into the mould tool by injection moulding so as to wholly encapsulate the wire frame and to form an article having an open central region cries-crossed by intersecting orthogonal ribs bounded on all sides by a rigid flange, the article being such that each of said ribs includes two parallel spaced apart wires of said frame assembly;
(d) supporting the wire frame assembly within the mould tool by means of retractable pins which protrude through the tooling wail to engage the assembly and accurately locate it within the mould tool, and the pins are refracted as the mould tool opens after the moulding step has been completed;
wherein the pins align with protruding wires making up the wire frame assembly and are separably jointed to the ends of the wires by means of sleeves of plastics material which is compatible with or the same polymer used to form the support frame, and opposite ends of the sleeves receive the pins and the reinforcing wire ends respectively, and wherein the passage through each sleeve is blocked so as to form two coaxial blind bores, each sleeve becomes embedded in the polymer during moulding and remains in the polymer as the pin which engages it is retracted as the tooling is opened, the blocked passage serving to encapsulate the end of the wire end located in tire inner end of the sleeve;
(e) permitting the polymer to cure;
and
(f) opening the tool;
and removing the article.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/025,070Filed 19 Dec 2001 · division
Priority: GB 97043321 Mar 1997
Published: US 2002/0088531 A111 Jul 2002
Granted: 6 Jul 2004
Term ends: Not estimatedThe source records don’t support an estimate.

Classification32 codes

B07B 1/4618
Constructional details of screening surfaces or meshes: manufacturing of screening surfaces
B01D 29/012
With flat filtering elements: making filtering elements
B01D 29/05
With flat filtering elements: supported
B01D 29/445
Edge filtering elements, i.e. using contiguous impervious surfaces: bar screens

Family

PCT/GB98/00601Parent of this division · filed 25 Feb 1998
US 2002/0088531 A1Pre-grant publication · published 11 Jul 2002
Application09/367,379Parent of this division
US 6,675,975 B1Related patent
US 6,759,000 B2This patent

From the US filing history. Foreign family members aren’t listed.