WO2007147196A1 - Thread forming wire thread insert - Google Patents

Thread forming wire thread insert Download PDF

Info

Publication number
WO2007147196A1
WO2007147196A1 PCT/AU2006/001527 AU2006001527W WO2007147196A1 WO 2007147196 A1 WO2007147196 A1 WO 2007147196A1 AU 2006001527 W AU2006001527 W AU 2006001527W WO 2007147196 A1 WO2007147196 A1 WO 2007147196A1
Authority
WO
WIPO (PCT)
Prior art keywords
thread
wire
insert
tapered flange
thread insert
Prior art date
Application number
PCT/AU2006/001527
Other languages
French (fr)
Inventor
Simon James Bowen
Peter Venetis
Original Assignee
Alcoa Fastening Systems - Australia Pty Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from AU2006903285A external-priority patent/AU2006903285A0/en
Application filed by Alcoa Fastening Systems - Australia Pty Ltd filed Critical Alcoa Fastening Systems - Australia Pty Ltd
Publication of WO2007147196A1 publication Critical patent/WO2007147196A1/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B37/00—Nuts or like thread-engaging members
    • F16B37/12—Nuts or like thread-engaging members with thread-engaging surfaces formed by inserted coil-springs, discs, or the like; Independent pieces of wound wire used as nuts; Threaded inserts for holes

Definitions

  • the present invention is directed to wire thread inserts used in the repair of pre-existing threaded bores having a damaged thread, or to form a new thread for a bore within a substrate.
  • Wire thread inserts are conventionally provided by wrapping a wire into a closed coil configuration, the coiled insert having an inner and outer surface.
  • the cross-section of the wire has a diamond shape and is coiled such that one portion of the coiled wire provides an inner helical thread for the inner surface of the insert, while the other portion of the coiled wire provides a second helical thread for the outer surface of the insert which is adapted to engage a helical thread provided in a bore within a substrate.
  • wire thread inserts are typically used to repair threaded bores where the thread has been damaged or stripped. They can also be used to provide a new thread for a bore.
  • the normal procedure for repairing an existing threaded bore and for installing such a wire thread insert is as follows: a) passing a drill bit through the bore to clean out and remove the remaining sections of the original helical thread; b) using a tap to provide a new helical thread within the drilled bore, this helical thread having a diameter greater than the original helical thread of the bore; c) inserting the wire thread insert by means of a installation tool which engages a tang or notch on the inner surface provided at the end of the insert and applying a torsional force to the insert to thereby twist and temporarily narrow the diameter of the insert thereby allowing the insert to enter and engage the female helical thread in that bore; d) releasing the insert such that it springs outwardly again to more tightly engaging the threaded bore; and e) finally breaking or twisting off the tang when and if provided at the end of the wire thread insert.
  • the torsional force applied to the wire thread insert initially twists and thereby compresses that insert such that it can be readily wound into the helical thread. Once the torsional force is removed from the thread insert, that insert expands outwardly to secure the engage the female helical thread provided within the threaded bore. This ensures that the thread insert remains securely in place when a bolt is subsequently inserted and engages the new female helical thread provided by the inside surface of that thread insert. A similar procedure is followed where the insert is being used to provide a new helical thread within a bore.
  • the present invention provides a wire thread insert for forming a helical thread, comprising a wire wound into a closed coil having an outer surface and an inner surface, wherein the wire has a first portion defining the inner surface of the thread insert when coiled, said first portion having a cross-section at least substantially in the form of a standard thread, the wire having an opposing second portion defining the outer surface of the thread insert and having a cross-section in the form of a tapered flange with at least one concave face.
  • the cross-section of the tapered flange is provided with opposing concave faces.
  • the cross-section of the tapered flange of the wire includes a base forming the junction between the first and second portions of the wire.
  • the length of the tapered flange measured from the free end of the tapered flange to said base may be directly proportional to the modulus of elasticity of the substrate material in which the insert is adapted to be installed.
  • the profile of the concave walls of the second side of the wire may be generally defined by the "rule of thirds", such that the thickness of the tapered flange measured in the pitch dimension (Ze parallel to the base) varies as a function of the distance away from the free end of the tapered flange in a 3:1 ratio.
  • the wire thread insert may be made of material including stainless steel or other metal.
  • the substrate materials may include but not be limited to polymers, non-ferrous alloys and ferrous alloys.
  • the profile of the tapered flange portion of the wire allows the wire insert to be inserted into a bore within a substrate, the profile of the tapered flange being adapted to plastically deform the material of said substrate as the wire thread insert is wound into the bore.
  • the tapered flange therefore forms a thread within the substrate material as the insert is installed. It should be noted that the thread is not being cut into the substrate material.
  • the substrate material is in fact plastically deforming around the tapered flange.
  • Figure 1 is a side cross-sectional view of a wire thread insert according to the present invention installed within a bore;
  • FIG. 2 is a detailed view designated "A" on Figure 1.
  • the thread forming wire thread insert 1 can be inserted into a bore 3 provided within a substrate 2.
  • the bore 3 may be drilled into the substrate 2 or may be integrally formed together with the substrate 2 prior to insertion of the wire thread insert 1 , the internal walls 5 are relatively smooth without the need for any helical thread to be provided within the bore 3.
  • the wire thread insert 1 is installed into the bore 3 by means of an installation tool (not shown) which has a mandrel which allows the setting and maintaining of the thread pitch of the wire thread insert 1 during installation thereof.
  • the mandrel dimensions are designed to maintain the gauge dimensions of the installed wire thread insert 1 , and this may vary from a standard thread hole wire thread insert.
  • the wire thread insert 1 is formed by wrapping a wire 7 into a closed coil having an inner surface 9 providing an internal helical thread, and an outer surface 11 which provides the thread forming arrangement according to the present invention.
  • the wire has a first portion 13 forming the inner surface 9 of the wire thread insert 1 , and a second portion 15 forming the outer surface 11 thereof.
  • the first portion 13 is in the form of a standard thread and is adapted to cooperate with the thread of a bolt or other threaded fastener.
  • the second portion 15 has a cross-section in the shape of a tapered flange which extends from a base 17 defined by the interface between the first and second portions 13, 15 to a tip 19 of the tapered flange 15.
  • the length 21 of the tapered flange 15 measured between the base 17 and tip 19 is directly proportional to the modulus of elasticity of the material forming the substrate 2, and the length 21 is therefore selected on this basis. A greater length 21 is used as the modulus of elasticity of the substrate 2 to which it is to be used increases.
  • Each tapered flange 15 has opposing flat concave faces 23 as best shown in Figure 2.
  • the shape of the cross-section of the tapered flange 15, and therefore the curvature of the concave faces 23, is determined on the basis of the "rule of thirds". More specifically, the thickness of the tapered flange 15 measured in a pitch dimension (Ze parallel to the base 17) varies as a function of the distance from the tip 19 in a 3:1 ratio.
  • the configuration of the tapered flange 15 allows the substrate material to plastically deform about the tapered flange 15 as the wire thread insert 1 is installed into the bore 3 without the need to pre-machine a helical thread within that bore.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Hand Tools For Fitting Together And Separating, Or Other Hand Tools (AREA)

Abstract

A wire thread insert (1) for forming a helical thread, comprising a wire (7) wound into a closed coil having an outer surface (9) and an inner surface (11 ), wherein the wire (7) has a first portion (13) defining the inner surface of the thread insert when coiled, said first portion having a cross-section at least substantially in the form of a standard thread, the wire having an opposing second portion (15) defining the outer surface of the thread insert and having a cross-section in the form of a tapered flange with at least one concave face (23).

Description

THREAD FORMING WIRE THREAD INSERT
FIELD OF THE INVENTION
The present invention is directed to wire thread inserts used in the repair of pre-existing threaded bores having a damaged thread, or to form a new thread for a bore within a substrate.
BACKGROUND OF THE INVENTION
Wire thread inserts are conventionally provided by wrapping a wire into a closed coil configuration, the coiled insert having an inner and outer surface. The cross-section of the wire has a diamond shape and is coiled such that one portion of the coiled wire provides an inner helical thread for the inner surface of the insert, while the other portion of the coiled wire provides a second helical thread for the outer surface of the insert which is adapted to engage a helical thread provided in a bore within a substrate.
These wire thread inserts are typically used to repair threaded bores where the thread has been damaged or stripped. They can also be used to provide a new thread for a bore.
The normal procedure for repairing an existing threaded bore and for installing such a wire thread insert is as follows: a) passing a drill bit through the bore to clean out and remove the remaining sections of the original helical thread; b) using a tap to provide a new helical thread within the drilled bore, this helical thread having a diameter greater than the original helical thread of the bore; c) inserting the wire thread insert by means of a installation tool which engages a tang or notch on the inner surface provided at the end of the insert and applying a torsional force to the insert to thereby twist and temporarily narrow the diameter of the insert thereby allowing the insert to enter and engage the female helical thread in that bore; d) releasing the insert such that it springs outwardly again to more tightly engaging the threaded bore; and e) finally breaking or twisting off the tang when and if provided at the end of the wire thread insert. The torsional force applied to the wire thread insert initially twists and thereby compresses that insert such that it can be readily wound into the helical thread. Once the torsional force is removed from the thread insert, that insert expands outwardly to secure the engage the female helical thread provided within the threaded bore. This ensures that the thread insert remains securely in place when a bolt is subsequently inserted and engages the new female helical thread provided by the inside surface of that thread insert. A similar procedure is followed where the insert is being used to provide a new helical thread within a bore.
A number of steps are therefore required to install the wire thread insert. It would however be advantageous to provide a wire thread insert which eliminates some of the above-noted installation steps thereby reducing installation and tooling costs.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a wire thread insert that does not require all the installation steps associated with conventional wire thread inserts.
With this in mind, the present invention provides a wire thread insert for forming a helical thread, comprising a wire wound into a closed coil having an outer surface and an inner surface, wherein the wire has a first portion defining the inner surface of the thread insert when coiled, said first portion having a cross-section at least substantially in the form of a standard thread, the wire having an opposing second portion defining the outer surface of the thread insert and having a cross-section in the form of a tapered flange with at least one concave face.
Preferably, the cross-section of the tapered flange is provided with opposing concave faces. The cross-section of the tapered flange of the wire includes a base forming the junction between the first and second portions of the wire. The length of the tapered flange measured from the free end of the tapered flange to said base may be directly proportional to the modulus of elasticity of the substrate material in which the insert is adapted to be installed. The profile of the concave walls of the second side of the wire may be generally defined by the "rule of thirds", such that the thickness of the tapered flange measured in the pitch dimension (Ze parallel to the base) varies as a function of the distance away from the free end of the tapered flange in a 3:1 ratio. The wire thread insert may be made of material including stainless steel or other metal. The substrate materials may include but not be limited to polymers, non-ferrous alloys and ferrous alloys.
The profile of the tapered flange portion of the wire allows the wire insert to be inserted into a bore within a substrate, the profile of the tapered flange being adapted to plastically deform the material of said substrate as the wire thread insert is wound into the bore. The tapered flange therefore forms a thread within the substrate material as the insert is installed. It should be noted that the thread is not being cut into the substrate material. The substrate material is in fact plastically deforming around the tapered flange.
BRIEF DESCRIPTION OF THE DRAWINGS
It will be convenient to further describe the invention with respect to the accompanying drawings which illustrate a preferred embodiment of the wire thread insert according to the present invention. Other embodiments of the invention are possible, and consequently, the particularity of the accompanying drawings is not to be understood as superseding the generality of the preceding description of the invention.
In the drawings: Figure 1 is a side cross-sectional view of a wire thread insert according to the present invention installed within a bore; and
Figure 2 is a detailed view designated "A" on Figure 1. DETAILED DESCRIPTION OF THE DRAWINGS
Referring to Figures 1 and 2, the thread forming wire thread insert 1 according to the present invention can be inserted into a bore 3 provided within a substrate 2. The bore 3 may be drilled into the substrate 2 or may be integrally formed together with the substrate 2 prior to insertion of the wire thread insert 1 , the internal walls 5 are relatively smooth without the need for any helical thread to be provided within the bore 3.
The wire thread insert 1 is installed into the bore 3 by means of an installation tool (not shown) which has a mandrel which allows the setting and maintaining of the thread pitch of the wire thread insert 1 during installation thereof. The mandrel dimensions are designed to maintain the gauge dimensions of the installed wire thread insert 1 , and this may vary from a standard thread hole wire thread insert. The wire thread insert 1 is formed by wrapping a wire 7 into a closed coil having an inner surface 9 providing an internal helical thread, and an outer surface 11 which provides the thread forming arrangement according to the present invention. The wire has a first portion 13 forming the inner surface 9 of the wire thread insert 1 , and a second portion 15 forming the outer surface 11 thereof. The first portion 13 is in the form of a standard thread and is adapted to cooperate with the thread of a bolt or other threaded fastener. The second portion 15 has a cross-section in the shape of a tapered flange which extends from a base 17 defined by the interface between the first and second portions 13, 15 to a tip 19 of the tapered flange 15. The length 21 of the tapered flange 15 measured between the base 17 and tip 19 is directly proportional to the modulus of elasticity of the material forming the substrate 2, and the length 21 is therefore selected on this basis. A greater length 21 is used as the modulus of elasticity of the substrate 2 to which it is to be used increases. Each tapered flange 15 has opposing flat concave faces 23 as best shown in Figure 2. The shape of the cross-section of the tapered flange 15, and therefore the curvature of the concave faces 23, is determined on the basis of the "rule of thirds". More specifically, the thickness of the tapered flange 15 measured in a pitch dimension (Ze parallel to the base 17) varies as a function of the distance from the tip 19 in a 3:1 ratio. The configuration of the tapered flange 15 allows the substrate material to plastically deform about the tapered flange 15 as the wire thread insert 1 is installed into the bore 3 without the need to pre-machine a helical thread within that bore.
Modifications and variations as would be deemed obvious to the person skilled in the art are included within the ambit of the present invention as claimed in the appended claims.

Claims

1. A wire thread insert for forming a helical thread, comprising a wire wound into a closed coil having an outer surface and an inner surface, wherein the wire has a first portion defining the inner surface of the thread insert when coiled, said first portion having a cross-section at least substantially in the form of a standard thread, the wire having an opposing second portion defining the outer surface of the thread insert and having a cross-section in the form of a tapered flange with at least one concave face.
2. A wire thread insert according to claim 1 , wherein the cross-section of the tapered flange is provided with opposing concave faces.
3. A wire thread insert according to claim 2, wherein the thickness of the tapered flange measured in a pitch dimension varies as a function of the distance away from a free end of the tapered flange in a 3:1 ratio.
PCT/AU2006/001527 2006-06-19 2006-10-16 Thread forming wire thread insert WO2007147196A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU2006903285 2006-06-19
AU2006903285A AU2006903285A0 (en) 2006-06-19 Thread forming wire thread Insert

Publications (1)

Publication Number Publication Date
WO2007147196A1 true WO2007147196A1 (en) 2007-12-27

Family

ID=38832987

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AU2006/001527 WO2007147196A1 (en) 2006-06-19 2006-10-16 Thread forming wire thread insert

Country Status (2)

Country Link
US (1) US20070292238A1 (en)
WO (1) WO2007147196A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009048160A1 (en) 2009-10-02 2011-04-07 Böllhoff Verbindungstechnik GmbH An insertable wire thread insert, method for its manufacture, component with an insertable wire thread insert and a method for its production

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102013219013A1 (en) * 2013-09-20 2015-03-26 Böllhoff Verbindungstechnik GmbH Spring connecting element

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0090698A1 (en) * 1982-03-23 1983-10-05 Otalu S.A. Self-tapping helical wire insert, and wire for its manufacture
EP0140812A1 (en) * 1983-09-16 1985-05-08 Rexnord Holdings Inc. Tangless helically coiled insert
FR2750747A1 (en) * 1996-07-04 1998-01-09 Snecma Assembly of helical thread coil insert to threaded cut=out in hollow bush to form final thread, usable in aircraft engines
EP1070861A2 (en) * 1999-07-20 2001-01-24 Emhart Inc. Coated fastener inserts and method of producing the same
EP1122449A2 (en) * 2000-02-04 2001-08-08 Emhart Inc. Anti-galling fastener inserts
US20020136615A1 (en) * 2001-03-23 2002-09-26 William Giannakakos Cold head stamped fastener inserts including selectively removable tangs
US20030086772A1 (en) * 2001-11-02 2003-05-08 William Giannakakos Helically coiled titanium wire fastener inserts
EP1589237A1 (en) * 2004-04-21 2005-10-26 Newfrey LLC Chromate free fluoropolymer coated fastener inserts
WO2005124165A1 (en) * 2004-06-15 2005-12-29 Böllhoff Verbindungstechnik GmbH Wire threaded insert made of magnesium or aluminium alloy

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US1082252A (en) * 1913-07-25 1913-12-23 Clemens W Ackermann Tie and tie-plate support.
US2581399A (en) * 1947-11-03 1952-01-08 Heli Coil Corp Thread insert for molded or cast material
US2672070A (en) * 1953-06-10 1954-03-16 Heli Coil Corp Wire coil screw thread insert for molded material
GB1010406A (en) * 1963-09-24 1965-11-17 C H Larsson Furniture fitting
GB2271159B (en) * 1992-09-04 1995-05-10 Multiclip Co Ltd Securing devices

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0090698A1 (en) * 1982-03-23 1983-10-05 Otalu S.A. Self-tapping helical wire insert, and wire for its manufacture
EP0140812A1 (en) * 1983-09-16 1985-05-08 Rexnord Holdings Inc. Tangless helically coiled insert
FR2750747A1 (en) * 1996-07-04 1998-01-09 Snecma Assembly of helical thread coil insert to threaded cut=out in hollow bush to form final thread, usable in aircraft engines
EP1070861A2 (en) * 1999-07-20 2001-01-24 Emhart Inc. Coated fastener inserts and method of producing the same
EP1122449A2 (en) * 2000-02-04 2001-08-08 Emhart Inc. Anti-galling fastener inserts
US20020136615A1 (en) * 2001-03-23 2002-09-26 William Giannakakos Cold head stamped fastener inserts including selectively removable tangs
US20030086772A1 (en) * 2001-11-02 2003-05-08 William Giannakakos Helically coiled titanium wire fastener inserts
EP1589237A1 (en) * 2004-04-21 2005-10-26 Newfrey LLC Chromate free fluoropolymer coated fastener inserts
WO2005124165A1 (en) * 2004-06-15 2005-12-29 Böllhoff Verbindungstechnik GmbH Wire threaded insert made of magnesium or aluminium alloy

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009048160A1 (en) 2009-10-02 2011-04-07 Böllhoff Verbindungstechnik GmbH An insertable wire thread insert, method for its manufacture, component with an insertable wire thread insert and a method for its production
WO2011038939A1 (en) 2009-10-02 2011-04-07 Böllhoff Verbindungstechnik GmbH Moldable wire thread insert, method for the production thereof, component comprising moldable wire thread insert and a method for the production thereof
US8931991B2 (en) 2009-10-02 2015-01-13 Böllhoff Verbindungstechnik GmbH Moldable wire thread insert, method for its production, component with a moldable wire thread insert as well as a method for its production
US9676128B2 (en) 2009-10-02 2017-06-13 Bollhoff Verbindungstechnik Gmbh Moldable wire thread insert, method for its production, component with a moldable wire thread insert as well as a method for its production
US10005211B2 (en) 2009-10-02 2018-06-26 Böllhoff Verbindungstechnik GmbH Moldable wire thread insert, method for its production, component with a moldable wire thread insert as well as a method for its production
DE102009048160B4 (en) 2009-10-02 2019-05-16 Böllhoff Verbindungstechnik GmbH Insertable wire thread inserts, component with an insertable wire thread insert and method of manufacturing a component with an insertable wire thread insert

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