FR2501253A1 - SLIDING CUSHION AND ITS USE IN A RAILWAY HANDLING SYSTEM - Google Patents

Abstract

1. Slide plate (19) usable in a railway points system, characterized in that it comprises a sliding surface (20) formed from ceramic material.

Description

The subject of the present invention is a cousin

  slip, which can be used especially in

  railway referral systems.

  Railway track systems generally include a straight counter needle associated with a curved needle and a straight needle associated with a curved counter needle which can

  be positioned between them in two different ways.

  to ensure or not the connection with a lane

deviation.

  In these systems, the needles are made of planed pieces in special profile rails that are supported by sliding bearings

  fixed on the support rails of the railway.

  Generally, these pads are made of cast iron and have on their bottom sole a recess from below to lighten the whole. To allow the needles to slip on the pad during the change of position of the switch, the upper soles of the pads are lubricated by

Appropriate fats.

  However, the pads currently used

  have the disadvantage of not presenting a

  sufficient resistance to erosion. Indeed, the film

  lubricating grease on the surface of the cushion

  net can retain the dust that accumulates on

  the way, in particular the sand, which generally

  the lower layer of the ballast. When dust as hard as sand accumulates in the lubricating grease film, this leads to a deterioration of the referral system because the surfaces of the needles and / or pads end up being

  eroded by these very hard particles, which is

  the operation of the switch because of the risk of seizure which would lead to

immobilization of the switch.

  To avoid this disadvantage, it has been envisaged to form on the surface of sliding bearings a plastic coating, for example

  polytetrafluoroethylene. However, the results obtained

  held with such bearings have not been satisfactory.

  sants. The present invention specifically relates to a sliding pad that can be used in particular

  in a railway referral system, which allows

  avoids the above-mentioned drawback.

  The sliding pad according to the invention

  is characterized in that it includes a surface

  slip made of ceramic material.

  According to a first embodiment of this

  cushion, it comprises a support provided with an

  and a piece of ceramic material fixed in said recess so as to constitute said surface

slip.

  According to a second embodiment of this

  cushion, it comprises a support provided with an

  and a plurality of pieces of ceramic material

  fixed in said recess so as to constitute

said sliding surface.

  Preferably, in this second embodiment of

  ceramic parts have rounded edges to facilitate sliding at the

-30 junction between two pieces.

  According to the invention, the ceramic material is a very hard material, which advantageously resists

  in addition to compression and atmospheric corrosion

than.

  As examples of potential materials

  oxides such as alumina, zirconium oxide, rare earth oxides and corundum, nitrides such as

  boron nitride and silicon nitride, and

  such as silicon carbide and boron carbide. Advantageously, for railroad switches, high hardness alumina is used which resists compression. Indeed, in this application, the pads must support

  very significant pressures that can go as far as

  than 150 bars in the thinned zone of the needles

  that the latter are loaded at 10 tons per wheel.

  The invention also relates to a system

  routing system with

  straight needle stitch associated with a curved needle, a curved counter-needle associated with a straight needle, a first series of sliding bearings for supporting the right counter-needle and the needle

  curve and a second series of glide pads

  to support the right needle and counter

  curved needle, characterized in that the sliding surfaces of the bearings of the first and second series are made of ceramic material, said surfaces having dimensions such that the

  needles are always supported on said surfaces

  these during the operation of the switch.

  Advantageously, each pad of the first or second series comprises a metal support on which is fixed the right counter-needle or the curved counter-needle, said support being provided with a recess in which are fixed a plurality of pieces of material ceramic arranged

  to form the sliding surface of said cushion

  net. According to an alternative embodiment of the switching system of the invention, the needle curves and

  the right needle also include

  ceramic material flush with their sur-

  faces that are in contact with the sliding bearings

  ment. According to this variant, the reliability and safety characteristics can be further improved.

  operation of the switch using a

  ceramic materials chosen so as to reduce the

reduce the coefficient of friction.

  In this case, it is possible to use, for example, alumina for producing the sliding surfaces of the bearings and to make the inclusions of material

  different, for example aluminum titanate.

  Other features and benefits of

  the invention will become more apparent on reading the

  following description given, of course, as an illustration

  process and not limiting, with reference to the appended drawing in which:

  FIG. 1 is a view from above of a system of

  trimming, - Figure 2 is a schematic representation in

  perspective of a sliding pad according to the

  FIG. 3 is a bottom view of the needle shown in FIG.

  FIG. 4 illustrates an embodiment of the

  sinet of the invention, and - Figure 5 illustrates another embodiment of the invention.

pad of the invention.

  In Figure 1, there is shown a path

  railway and the A switching system associated with it

  ted. Before switch A, the railway is

  killed by two rails 1 and 3 which are fixed on

  5 by means of fixing devices

  7. The following switch system A includes a straight counter-needle 11, a curved needle 13, a curved contrail needle 15, and

  a straight needle 17. In the part of the

  ge, the right and curved counter-needles are respectively fixed on a first series and a second series of sliding bearings 19, themselves fixed

  by bolts on the sleepers of the railway line

  SOE. Needles 13 and 17 are supported respectively

  by the first and second series of cousins

  slip patterns 19, and they can be moved

  between a first position in which the

  guille 13 is in contact with the counter needle 11

  while the needle 17 is removed from the counter

  needle 15, at a second position (shown in dashed lines in the drawing) in which the needle

  17 is in contact with the counter needle

  be 15 while the needle 13 is removed from the con-

  right hand needle 11. This displacement is obtained at

  means of a maneuvering device comprising a

  21 which actuates the associated operating rod 23

to the spacer rod 25.

  After the referral system, each

  full of rails which constitutes the main track I and the deviation II, is again fixed on the sleepers 5

  by means of lag bolts 7.

  As can be seen in Figure 2, each

  that sliding pad 19 supports a counter against

  guille and the needle associated with it, for example

  the right counter-needle 11 and the curved needle 13.

  The counter-needle 11 is secured to the cushion

  net slip by a suitable device such as 31, while the needle 13 can move on the

  pad 19 between two extreme positions. The counter

  needle 11 comprises, like the rail 1, an upper part

  mushroom-shaped lla which supports the contact of the wheel, a thinned middle portion llb which constitutes the core, and an enlarged lower portion ilc which constitutes the pad used for fixing the rail on the sleepers. Similarly, the needle comprises an upper portion 13a whose thickness increases gradually and regularly from its point

  contact with the counter needle which is associated with

  a middle part 13b and a lower part

skate-shaped 13c.

  In the devices of the prior art, the sliding bearings 19 were made of steel

  and provided with lubricating grease films on their

  19a to facilitate the sliding of the needles such as 13 on the bearings 19. However, since the film of lubricant could retain dust, especially sand, was obtained at

  after a certain period of operation a deterioration

  the upper surface of the pad and / or the sole of the needle, which could lead to

  seizure and immobilization of the

ge.

  According to the invention, this disadvantage is avoided.

  by means of at least one modification of the upper surface 19a of the sliding bearings 19. For this purpose, each sliding bearing 19 comprises a sliding surface 20 made of ceramic material, for example

  example in alumina of great hardness.

  Thus, a low coefficient of friction can be obtained without using an intermediate layer of lubricant and thereby avoid problems

  erosion related to the use of lubricant and

  Traversing a seizure of the switch system.

  In addition, the fact of reducing the coefficient of friction makes it possible to use less energy to move the needles between their two extreme positions. According to the invention, a layer of lubricant can also be used between the surface of the pad and the surface of the moving needle to improve sliding. Indeed, given the hardness of the ceramic sliding surface, it avoids the

  problems of seizure likely to occur

  sound of anchoring mineral particles in the film

of lubricant.

  According to an alternative embodiment of the system

  of the invention, the needles comprise

  they also include inclusions of ceramic material flush with their surfaces intended to come into

  contact with sliding bearings 19.

  This variant embodiment is

  3 is a view from below of the needle 13 of FIG. 2. In this figure, it can be seen that the sole 13c of the lower part or shoe of the needle 13 comprises a recess 14 on the inside. of which is fixed a ceramic piece

22, high hardness.

  In this case, it is preferable to use

  the piece 22 another ceramic material than the one used

  for part 20 to further reduce the coef-

  friction, for example, aluminum titanate can be used for the workpiece 22 when the bearing surface 20 of the sliding bearing is

made of alumina.

  Although in this drawing there is shown a single recess and a single ceramic part, it goes without saying that the sole 13c of the needle 13 comprises a plurality of recesses 14, these recesses being made at the sliding bearings 19 and

  each having a piece of ceramic material 22.

  However, it should be noted that the modification of the needles by ceramic inserts poses certain problems to preserve the properties

  mechanical parts of the moving parts of the switch rails.

  Also, it is generally best not to modify

  proud profile of the needles by creating recesses in their soles. In order to avoid these recesses, the ceramic elements can be glued directly onto

the sole of the needles.

  The sliding pad 19 shown in

  Figure 2 can be obtained as follows.

  A recess is formed at the upper part of a pad 19 made of steel, and then

  in the bottom of the recess of the son in plastic material

  tick, for example nylon threads. We prepare sepa-

  rély a piece of ceramic material, for example alumina having a shape that corresponds substantially to that of the recess, then introduced some

  quantity of glue constituted for example by a residence

  epoxy in the center of the recess, and

  this. the ceramic piece in the recess in the

  priming to ensure its bonding by means of the epoxy resin.

  It is specified that nylon threads are intended

  to promote the spreading of the adhesive over the entire surface of the recess, which ensures a good bonding of the ceramic part. For this reason,

  these threads are generally 5/10 mm thick.

  The inclusions of ceramic material in the needle 13 can be made in the same way after having made recesses in the soleplate

13c of the needle 13.

  Although in these two examples we have

  polished the establishment of a single piece of ceramic in the corresponding recesses, we can use several ceramic pieces by recess like this

  is shown in Figures 4 and 5.

  In the case of Figure 4 which shows another embodiment of the pad 19, it also comprises a support of appropriate shape for

  secure the attachment of the counter-needle, and this

  port is provided with a recess in which are fixed two ceramic plates 20a and 20b arranged so that the junction between the wafer

  extends in a direction parallel to the direction of de-

  placement of the needle between its two ex-

  treme. In this way we avoid the problems of sliding

  the needle, which could be

  of the junction between two platelets.

  However, as shown in FIG. 5, the ceramic plates can be arranged in a

  different, for example with junctions between

  extending in perpendicular directions

  in the direction of movement of the needle. Toute-

  it is preferable in this case to use plates 20a, 20b ... whose edges are rounded at the level of the junctions between successive plates in order to avoid the problems of sliding that might arise due to a difference thick between

two consecutive pads.

  When the pads have more than one

  ceramic plates, they can be

  in the same way as the pads having a single plate by assembling the pads in the recess provided with plastic son and

  glue, and then compressing the whole.

Claims (10)

  1. Usable sliding bushing   in a railroad switching system, characterized in that it comprises a sliding surface   sement (20) made of ceramic material.   2. Bearing according to claim 1,   characterized in that it comprises a support (19) provided with a recess and a piece (20) of ceramic material   fixed in said recess so as to constitute sliding surface.   3. Bearing according to claim 1,   characterized in that it comprises a support (9) provided with a recess and a plurality of pieces (20a, 20b) of ceramic material fixed in said recess of   to constitute said sliding surface.   4. Bearing according to claim 3,   characterized in that said pieces have sharp edges   rounded at their junctions with the pieces adjacent.   5. Bearing according to any one of the   Claims 1 to 4, characterized in that the material   ceramic is an oxide, a carbide or a nitride.   6. Bearing according to any one of   Claims 1 to 4, characterized in that the material Ceramic is alumina.   A track referral system comprising a right counter-needle (11) associated with a curved needle (13), a curved counter-needle (15) associated with a straight needle (17), a first series of bushings sliding (19) to support the right counter-needle and the curved needle and a second series of sliding bearings (19) for supporting the right needle and the counter-needle   curve, characterized in that the sliding surfaces   20 of the pads of the first and second series are made of ceramic material, said surfaces having dimensions such that the needles (13 or 17) are always supported on the   said surfaces (20) during the operation of the guillage.   8. Referral system according to the   7, characterized in that each pad (19) of   the first or second series includes a   metal port on which the counter-needle is   the right (11) or the curved counter-needle (15), the   said support being provided with a recess in which are fixed a plurality of pieces (20a, 20b) of ceramic material arranged to form the surface of sliding of said pad.   9. Referral system according to any one   of claims 7 and 8, characterized in that   that the curved needle (13) and the right needle (17) also include inclusions (22) of ceramic material flush with their surfaces which are   contact with the sliding bearings.   10. The system of claim 9, wherein   characterized in that the ceramic material of said   is different from the ceramic material   the sliding surface of said pads.