EP0880621B1 - Herstellungsverfahren für elastische schienenklammer - Google Patents

Herstellungsverfahren für elastische schienenklammer Download PDF

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Publication number
EP0880621B1
EP0880621B1 EP97904527A EP97904527A EP0880621B1 EP 0880621 B1 EP0880621 B1 EP 0880621B1 EP 97904527 A EP97904527 A EP 97904527A EP 97904527 A EP97904527 A EP 97904527A EP 0880621 B1 EP0880621 B1 EP 0880621B1
Authority
EP
European Patent Office
Prior art keywords
clamp
rail
blank
workpiece
base portion
Prior art date
Legal status (The legal status 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 status listed.)
Expired - Lifetime
Application number
EP97904527A
Other languages
English (en)
French (fr)
Other versions
EP0880621A1 (de
Inventor
Hartley Frank Young
Barry Marshall
Brian George Conroy
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pandrol Ltd
Original Assignee
Pandrol 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 PCT/GB1996/000319 external-priority patent/WO1997030224A1/en
Priority claimed from GBGB9620203.1A external-priority patent/GB9620203D0/en
Application filed by Pandrol Ltd filed Critical Pandrol Ltd
Publication of EP0880621A1 publication Critical patent/EP0880621A1/de
Application granted granted Critical
Publication of EP0880621B1 publication Critical patent/EP0880621B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01B—PERMANENT WAY; PERMANENT-WAY TOOLS; MACHINES FOR MAKING RAILWAYS OF ALL KINDS
    • E01B9/00—Fastening rails on sleepers, or the like
    • E01B9/02—Fastening rails, tie-plates, or chairs directly on sleepers or foundations; Means therefor
    • E01B9/28—Fastening on wooden or concrete sleepers or on masonry with clamp members
    • E01B9/30—Fastening on wooden or concrete sleepers or on masonry with clamp members by resilient steel clips
    • E01B9/303—Fastening on wooden or concrete sleepers or on masonry with clamp members by resilient steel clips the clip being a shaped bar
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01B—PERMANENT WAY; PERMANENT-WAY TOOLS; MACHINES FOR MAKING RAILWAYS OF ALL KINDS
    • E01B9/00—Fastening rails on sleepers, or the like
    • E01B9/02—Fastening rails, tie-plates, or chairs directly on sleepers or foundations; Means therefor
    • E01B9/28—Fastening on wooden or concrete sleepers or on masonry with clamp members
    • E01B9/30—Fastening on wooden or concrete sleepers or on masonry with clamp members by resilient steel clips
    • E01B9/306—Fastening on wooden or concrete sleepers or on masonry with clamp members by resilient steel clips the clip being a shaped plate

Definitions

  • This invention relates to manufacturing elastic rail clamps used in rail fastening systems, and particularly, although not exclusively, to a method of manufacturing rail clamps of the kind which are applied at right angles to the rails.
  • a method of manufacturing a rail clamp for fastening a rail to an underlying rail plate or rail tie comprising a base portion, adapted to seat in a slot in the rail plate or rail tie or in an anchoring device secured to the rail plate or rail tie, and a pair of substantially parallel members which extend from the base portion to a rail engaging portion, the parallel members being curved so that the rail engaging portion lies adjacent to the base portion, the method comprising: i) forming a workpiece by bending a length of bar stock to provide a pair of limbs; ii) pressing the workpiece thereby to flatten and/or reduce the thickness of the bar stock to form a blank; and iii) deforming the blank to form the clamp.
  • Previously considered manufacturing methods for producing a rail clamp of the type described in US 4,313,563 also suffer from the disadvantage that the clamp must undergo a "coining" operation to prevent undue stress concentrations being built up in the vicinity of sharp corners which result from a stamping process.
  • previously considered manufacturing methods required the formed clamp to undergo a "scragging" operation in which the clamp is overdeflected in order to induce a permanent deformation of its shape and an advantageous initial stress distribution in the clamp.
  • use of a method embodying the present invention can avoid the need for such coining and/or scragging operations if the bar stock is round and the workpiece is pressed such that the blank has rounded edges.
  • Figs. 1 to 5 Steps of a previously-considered method of manufacturing an elastic rail clamp are shown in Figs. 1 to 5.
  • the method starts with the production of a rectangular blank 1 (Fig. 1).
  • the blank would normally be formed from steel.
  • Each U-shaped blank 2 forms the basis of a rail clamp.
  • the U-shaped blank is cropped to length and the sharp edges are coined to produce smooth edges (Fig. 3).
  • the cropping and coining operations are usually done with a hot blank.
  • the rounding of the edges by the coining operation is necessary to avoid undue stress concentrations in the finished clamp.
  • Coining is a well-established process which attempts to improve a sheared edge to that of an edge normally associated with hot rolled steel.
  • the process is usually carried out in a power press employing a pair of dies.
  • the raw blank is placed in the dies and squeezed to form the round edges on the blank. This operation is critical to the fatigue life of a spring clamp manufactured from sheared flat material and requires a high degree of quality control during processing.
  • the cropped and coined blank is then hot formed into the clamp shape shown in Fig. 4, by bending the free ends over to form toe portions 7 which bear on the rail when the clamp is in use.
  • a base portion is produced by bending the central portion of the U-shaped blank. The base portion is for engagement with the baseplate in which the clamp will be used.
  • the clamp is then subjected to a scragging operation in which the base portion 5 of the clamp is held rigidly between two jaws 6.
  • a force is applied to the toe portions 7 so as to overdeflect the clamp.
  • the force is then released.
  • the force may be applied and released more than once, for example three times, and then the clamp is removed from the jaws 6.
  • Such an operation produces a clamp 8 having the required initial stress distribution and shape.
  • Figs. 6, 7, 8 and 9 illustrate various steps of manufacturing methods embodying the present invention.
  • a round bar of material is bent, at a position between its ends, to form a starting workpiece 10 of generally U-shaped form, having two limbs 14 interconnected by an arcuate portion 16.
  • the limbs 14 are parallel, and in the Fig. 6b workpiece the limbs 14 converge towards their free ends.
  • Figs. 7a and 7b show blanks 11 produced from the workpiece of Fig. 6a and 6b respectively.
  • the blanks are produced by heating the workpiece 10 and pressing it in an open die pressing operation.
  • the configuration of the plates of the press depends upon the final clamp shape which is required.
  • An example of such a press is shown in side elevation in Fig. 8.
  • the workpiece is placed in a lower die 22.
  • An upper die 21 is brought into contact with the workpiece 10 in the direction of arrow f in Fig. 8.
  • the blank 11 is pressed until the upper die 21 reaches stops 24 on the lower die 22.
  • the shaping of the pressure surface 23 of the upper die imparts the required shape to the blank 11.
  • the shaping of the pressure surface 23 has been exaggerated in Fig. 8 for the sake of clarity.
  • Other forms of shaped pressure surface would be used to form the shapes of blank 11 shown in Figs. 7a and 7b.
  • the inner and outer side faces 18, 20 of the limbs 14 and the inner surface of the arcuate portion 16 are not constrained by the plates of the press, and so the material of the workpiece 10 can flow unimpeded in the direction away from the centreline of the limbs 14 and inwardly of the arcuate portion 16 as the workpiece is pressed. Consequently, while the upper and lower faces of the workpiece 10 are flattened, the inner and outer side faces assume a rounded shape with no sharp edges.
  • the workpiece 10 may be flattened by means of a closed die pressing operation to produce a blank 11 as shown in Fig. 9a.
  • Figs. 9b and 9c show cross-sections through the lines IX b - IX b and IX c - IX c respectively.
  • the shape of the die used in the closed die pressing operation is such that the excess material overflows about the centre line of the blank and all the external edges of the blank have appropriate radii, since the die itself may be made so as to have no sharp edges, all being rounded appropriately.
  • a final "clipping" operation to remove excess material is required before the blank is hot formed into the final clip shape.
  • the thickness of the blank 11 may be varied according to the geometric shape requirements of the clamp and the stress levels which will be present in the various parts of the finished and installed clamp.
  • an end region 12 of the blank 11, corresponding to the arcuate portion 16 of the workpiece 10 of Fig. 6a, has been tapered. Such tapering may be required so that the clamp can be engaged with a baseplate.
  • the shape of the remaining parts of the blank 11 are chosen to optimise the stiffness of and the stress distribution in the finished clamp. For example, high stress regions may be thicker than low stress regions. Thinner low stress regions would allow greater deflection of the clamp when in use.
  • the flattened blank 11 is formed into a clamp 13 of the required shape.
  • the clamp shown in Fig. 10 is of the type described in US Patent No. 4,313,563, although the method would be applicable to other shapes of clamp, for example those described in International Patent Application No. PCT/GB96/00319 or U.S. Patent No. 3,067,947.
  • the clamp 13 is formed by bending the free ends of the blank 11 to form toe portions 14 which will bear on the rail when the clamp is in use.
  • a base portion is formed by bending the tapered end portion 12 of the blank 11 over the central portion of the blank.
  • Figs. 6 to 10 The advantage of the methods described with reference to Figs. 6 to 10 is that the blank produced has smooth rounded edges which have not been sheared. The rounded edges serve to prevent stress concentrations, but do not require coining to achieve this effect. Moreover, blanks produced by an open die pressing operation (Figs. 7a, 7b & 8), rather than a closed die pressing operation (Figs. 9a, 9b and 9c), do not require trimming.
  • the blank 2 (Fig. 2) used in the previously-considered manufacturing method is cut from a rolled steel sheet produced by rolling steel ingots. Such ingots contain impurities or inclusions particularly in central regions of the ingots. As shown in Fig. 11, these inclusions 31 are concentrated in a central region of the rolled sheet 30. Blanks 32 and 33 are cut from the sheet 30, and so the finished clamp will contain inclusions at its edges as shown in Fig. 12. Lines AA and BB in Fig. 11 show the positions of highest stress in the finished clamp. As will be appreciated from Fig. 11 there are three sheared edges having inclusions 31 in the regions of highest stress in the finished clamp. Fatigue failures can initiate and grow from these inclusions.
  • the inclusions are kept within the clamp and are not present at the edges of the finished clamp.
  • inclusions 31 in the bar stock are concentrated within the bar 34.
  • the inclusions 31 are kept within the pressed blank 35 and hence away from the edges of the finished clamp, as shown in Fig. 14. Such a distribution of inclusions in the clamp reduces the likelihood of fatigue failure of the clamp.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Forging (AREA)
  • Railway Tracks (AREA)
  • Clamps And Clips (AREA)
  • Vehicle Interior And Exterior Ornaments, Soundproofing, And Insulation (AREA)
  • Body Structure For Vehicles (AREA)

Claims (6)

  1. Verfahren zur Herstellung einer Schienenklammer (13) für die Befestigung einer Schiene auf einer darunterliegenden Schienenplatte oder Schienenverbindung, wobei die Klammer (13) einen Basisabschnitt (12) umfasst, eingerichtet für einen Sitz in einem Schlitz in der Schienenplatte oder Schienenverbindung und ein Paar im Wesentlichen paralleler Glieder (14), die sich vom Basisabschnitt (12) zum Schieneneingriffsbereich erstrecken, wobei die parallelen Glieder (14) so gekrümmt sind, dass der Schieneneingriffsbereich dem Basisabschnitt (12) benachbart liegt, und das Verfahren umfasst:
    i) das Ausbilden eines Werkstücks (10) durch Biegen einer Strecke eines Stabstocks, so dass ein Schenkelpaar erhalten wird;
    ii) Pressen des Werkstücks (10), so dass es abgeflacht und/oder die Dicke des Stabstocks vermindert wird und ein Rohling (11) erhalten wird; und
    iii) Verformen des Rohlings (11), so dass man die Klammer (13) erhält.
  2. Verfahren nach Anspruch 1, wobei der Stabstock rund ist und das Werkstück (10) so gepresst wird, dass der Rohling (11) runde Kanten hat.
  3. Verfahren nach Anspruch 1 oder 2, wobei beim Pressschritt das Material des Werkstücks (10) sich frei in einer Richtung parallel zur Ebene, in der die Mittellinien der Schenkel sind, verformen kann.
  4. Verfahren nach irgendeinem der vorhergehenden Ansprüche, wobei der Pressschritt den Betrieb einer offenen Formpresse beinhaltet.
  5. Verfahren nach irgendeinem der Ansprüche 1 bis 3, wobei der Pressschritt den Betrieb einer geschlossenen Formpresse beinhaltet.
  6. Verfahren nach Anspruch 5, wobei nach dem Presschritt überschüssiges Material vom Rohling (11) abgezwickt wird.
EP97904527A 1996-02-13 1997-02-11 Herstellungsverfahren für elastische schienenklammer Expired - Lifetime EP0880621B1 (de)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
PCT/GB1996/000319 WO1997030224A1 (en) 1996-02-13 1996-02-13 Elastic rail clamps
WOPCT/GB96/00319 1996-02-13
GB9620203 1996-09-27
GBGB9620203.1A GB9620203D0 (en) 1996-09-27 1996-09-27 Manufacturing elastic rail clamps
PCT/GB1997/000381 WO1997030225A1 (en) 1996-02-13 1997-02-11 Manufacturing elastic rail clamps

Publications (2)

Publication Number Publication Date
EP0880621A1 EP0880621A1 (de) 1998-12-02
EP0880621B1 true EP0880621B1 (de) 2000-09-06

Family

ID=26308440

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97904527A Expired - Lifetime EP0880621B1 (de) 1996-02-13 1997-02-11 Herstellungsverfahren für elastische schienenklammer

Country Status (8)

Country Link
EP (1) EP0880621B1 (de)
AU (1) AU1730297A (de)
BG (1) BG102681A (de)
DE (1) DE69703029D1 (de)
EA (1) EA000383B1 (de)
PL (1) PL183779B1 (de)
TR (1) TR199801560T2 (de)
WO (1) WO1997030225A1 (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2270299A1 (en) 1998-10-14 2000-04-14 Jude Igwemezie Rail retaining device
CN102642122B (zh) * 2012-04-25 2014-04-16 安阳市利达铁路器材有限责任公司 轨卡切割工艺

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3982692A (en) * 1974-07-19 1976-09-28 R. Stahl Aufzuege Gmbh Clamping means for elevator guide rails and the like
US4313563A (en) * 1978-06-27 1982-02-02 Ralph Mckay Limited Rail fastener
DE3606964A1 (de) * 1985-03-06 1986-09-11 Günter Dipl.-Ing. 5600 Wuppertal Marcus Verfahren und gesenk zum herstellen einer winkelfuehrungsplatte
AU630250B2 (en) * 1989-11-13 1992-10-22 General And Railway Supplies Pty Ltd Resilient rail retaining clip

Also Published As

Publication number Publication date
DE69703029D1 (de) 2000-10-12
EP0880621A1 (de) 1998-12-02
AU1730297A (en) 1997-09-02
EA199800716A1 (ru) 1999-04-29
EA000383B1 (ru) 1999-06-24
PL328327A1 (en) 1999-01-18
TR199801560T2 (xx) 1998-11-23
PL183779B1 (pl) 2002-07-31
BG102681A (en) 1999-04-30
WO1997030225A1 (en) 1997-08-21

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