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Document Type and Number:
WIPO Patent Application WO/2021/059141
Kind Code:
An improved attaching assembly for clamping a railway rail track (R) to a rail road tie (T), comprising a pair of attachment devices (1) each one provided with • at least an anchoring element (2d, 12c') configured to be securely fastened to said rail road tie (T), • a biasing element (5) arranged to impart a holding force, and • a lever element (3,13) having a distal end (3a1) and a proximal portion, and • a fulcrum element (2c, 12c) integral with said anchoring element (2), said lever element (3,13) being engaged with said fulcrum element (2c, 12c) so that said distal end (3a') and said proximal portion are arranged on opposite sides of said fulcrum element (2c, 12c), said distal end (3a') facing one side of said rail road tie (T), wherein said proximal portion of the lever element (3,13) has a threaded hole and said biasing element is a screw element (5) configured to be engaged with said threaded hole.

Application Number:
Publication Date:
April 01, 2021
Filing Date:
September 23, 2020
Export Citation:
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International Classes:
E01B9/10; E01B9/28; E01B9/12
Foreign References:
Attorney, Agent or Firm:
FAGGIONI, Carlo Maria et al. (Via S. Agnese 12, Milano, IT)
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1. Improved attaching assembly for clamping a railway rail (R) to a rail road tie (T), comprising a pair of attachment devices (1) each one provided with

- at least an anchoring element (2d, 12c') apt to be securely fastened to said rail road tie (T),

- a biasing element (5) arranged to impart a holding force, and

- a lever element (3, 13) provided with a distal end (3a') and with a proximal portion whereon said biasing element (5) acts, and

- a fulcrum element (2c, 12c), characterised in that said fulcrum element (2c, 12c) is integral with said ancho ring element (2), said lever element (3, 13) is engaged with said fulcrum element (2c, 12c) so that said distal end (3a') and said proximal portion are arranged on opposite sides of said fulcrum element (2c, 12c), said distal end (3a') facing one side of said rail road tie (T), and said proximal portion of the lever element (3, 13) has a threaded hole and said biasing element is a screw element (5) apt to be engaged with said threaded hole.

2. Assembly as in 1, wherein said threaded hole is made in a nut (3b, 13b) integral with said lever element (3, 13).

3. Assembly as in 1 or 2, wherein said fulcrum element makes up part of a U-shaped element (2c, 12c).

4. Assembly as in 3, wherein said anchoring element is a shoulder element (2, 12) provided with a base plate (2a, 12a) wherefrom said U-shaped element (2c, 12c) with a fulcrum element projects.

5. Assembly as in 4, wherein said U-shaped element (12c) runs through a slit (12a') of said base plate (12a).

6. Assembly as in 4 or 5, wherein said base plate (2a, 12a) has a recess (2b, 12b) on an upper surface thereof, apt to house an end of said screw element (5).

7. Assembly as in any one of the preceding claims, further more comprising an insulating plate (4) which defines a resting surface for said distal end (3a') of the lever element (3, 13).

8. Assembly as in 7, wherein said insulating plate (4) has an L-shaped profile with a foot portion (4a) and a web portion


9. Assembly as in any one of the preceding claims, wherein said lever element (3) is shaped as an oval ring (3a).

10. Assembly as in any one of the preceding claims dependant from claim 4, wherein said base plate (2a) has an adjustable configuration wherein an abutment side thereof takes up different distances from a constraint point of the anchoring element (2d, 12c') to said rail road tie (T).




The present invention relates to the sector of railway ar mament, in particular it refers to improved attachment means for the anchoring of railway tracks to the underlying railroad ties. STATE OF THE PRIOR ART

In the field of railway material manufacturing, in particu lar of the railway armament required for the mounting, fastening and adjustment of the railway, increasing attention has been de voted to the optimisation of devices, members and equipment in order to achieve an ever more controlled, comfortable and effi cient viability of railway trains.

Therefore, in its apparent simplicity, the railway super structure has proved to have great potential for performance im provement, both in terms of running speed and of vehicle transport capacity. As a consequence, railway armament members must guaran tee high efficiency and high strength to meet the high standards required by modern railway transport.

As known, the railway superstructure consists of a pair of parallel rails, which are secured onto railroad ties so as to form a rigid frame; railroad ties in turn are normally resting and retained on clinker ballast, which is put between the foundation ground and the railroad ties, so as to allow both the distribution of vertical loads and the maintenance of the geometric conditions of the rails without excessive constraint rigidity, which would suffer due to the serious efforts and vibrations transferred upon the passage of a heavy train. Rails are constrained to railroad ties by means of fastening means.

Up until today, in some applications it is resorted to ela stic-type, indirect attachment means. Said attachment means typi cally comprise fastening members which do not act rigidly directly onto the rail, but act indirectly through members with elastic deformation, such as metal clips and clamps, which hook the foot of the rail to the railroad tie.

Sometimes it is also provided to arrange a sub-rail plate between the rail and the railroad tie.

It has been detected that, over a conventional rigid faste ning member, for example of the type K, the elastic attachment joints absorb more the vibrations transmitted by the rail upon convoy passage.

In general, the elastic member deforms differently depending on the type of fastening. For example, for a Nabla type of atta chment, a metal clamp is used, of a substantially planar shape and arranged parallel to the resting plane of the rail, which clamp is elastically deformed by the end nut screwed onto a ver tical bolt; for a Vossloh type of attachment, a metal clasp is used, which is deformed by an ankle screwed in a dowel embedded in the railroad tie; for some Pandrol types of attachments a metal clip is used, which is deformed by the interaction between a metal shoulder member - embedded in the railroad tie - and the rail foot.

However, it has been detected that the previously cited at tachment members have some drawbacks.

For example, attachment members of the Vossloh and Nabla type, or other members of a similar design, have elastic fastening members which manage to share the applied load rather effectively, but require frequent maintenance. As a matter of fact, the parti cular arrangement of the deformable fastening members facilitates the transmission of the vibrational-acoustic disturbances di rectly along the threaded sections of the junction members, cau sing as a result an excessive accumulation of energy, which leads to the loosening of the clamping.

In addition, some prior art solutions use a considerable number of metal components for assembling the attachment assembly, for example, bolts, bolts, washers, nuts, guide plates: that is disadvantageous from a production point of view, but also in the use of labour for installation and maintenance.

Moreover, some of these attachment assemblies require high axial clamping forces and clamping torque for introducing bolts - or screws in general - into railroad tie recesses, thus requiring further energy consumption. The attachment assemblies of the Pandrol type have a con structively simpler structure and offer a greater vertical elastic deformation, capable of better absorbing the vibrations of the running train. However, due to the particular structural configu ration, the joining points between the clip and the rotation eye let are subject to continuous stresses, even of a high intensity, which represent weakness points of the system.

Also in this case, system assembly requires to apply remar kable energy, which is used for loading the elastic fastening element so that it in turn imparts a sufficiently strong action.

Therefore, the indirect fastening attachment assemblies of the elastic type of a prior art, such as those previously reported, although they make up effective holding solutions, do not prove fully satisfactory, especially due to the energy required for the installation thereof (and then also in the maintenance), which then implies the use of heavy and energetically expensive tools.

Other prior art attachment assemblies are disclosed in US3395864, US391912 and FR2165101. EP12265 discloses an attachment assembly which conceptually provides to exploit a lever effect for imparting a fastening pressure onto the rail; however, the proposed configuration resorts to a spring for imparting the clam ping force and has a complex structure to put into practice, which is not viable from an industrial point of view.

The need is therefore felt to provide an improved attachment assembly which overcomes the drawbacks of the prior art and, in particular, which has a suitable configuration to use a small number of components, easily installed on site and which requires small mounting energy.


The above-reported objects, according to the present invention, are carried out by means of an improved attachment assembly for railway tracks, which has the features defined in the attached main claim. Other preferred features of the improved attachment assembly according to the invention are defined in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS Further features and advantages of the invention will in any case be more evident from the following detailed description of a preferred embodiment of the same, provided purely as a non-limi- ting example and illustrated in the attached drawings, wherein: fig. 1 is a cross-section partly elevation view of an impro ved attachment assembly according to a first embodiment of the present invention, installed on a rail; figs. 2A and 2B are partial views, similar to that of fig. 1, in two different mounting steps of the improved attachment assembly according to the present invention; figs. 3A and 3B are bottom plan and top plan views, respec tively, of a lever element of the improved attachment assembly according to the embodiment illustrated in fig. 1; figs. 3C and 3D are a section view, taken along the A-A line and the B-B line, respectively, of figs. 3A and 3B; figs. 4A-4D are front elevation, side elevation, bottom plan and longitudinal cross-section axonometric views, respectively, partly in section, of a shoulder element of the attachment assem bly according to the embodiment of fig. 1; fig. 5 is a view similar to that of fig. 1 of a second embodiment of the invention; fig. 6 is a plan view of a shoulder element according to the embodiment of fig. 5; fig. 6A is a section view taken along the A-A line of fig.

6; fig. 6B is a section view taken along the B-B line of fig.

6; fig. 6C is a section view taken along the C-C line of fig.

6; fig. 7 is a plan view of a lever element according to the embodiment of fig. 5; figs. 8A and 8B are plan and side elevation views, respec tively, of a threaded component to be engaged with the lever element of fig. 7; fig. 8C is a section view taken along the C-C line of fig. 8B; and figs. 9A and 9B are front elevation and side elevation views, respectively, of a U-shaped element according to the embodiment of fig. 1, partly embedded in a railway railroad tie.


In fig. 1 an exemplifying rail R is illustrated in a cross- section, installed on a railroad tie T, for example a CAP railroad tie (made of pre-stressed reinforced concrete). The rail consists, in a traditional manner, of a part of part Rl, a stem or web part R2 and a mushroom-shaped head portion R3.

Underneath foot Rl a plate of vibration dampening material is possibly provided, for example an insulating panel G of PGS- type rubber, which also makes up a valid insulation from eddy currents. It is understood that this exemplifying representation is not limiting.

On the two opposite sides of foot Rl identical and mirror like attachment devices 1 are provided, meant to constrain rail R to railroad tie T. The attachment devices 1 are provided in pairs on each rail in correspondence of each railroad tie T, and are hence mutually spaced apart along the entire extension of rail R with the same pitch of railroad ties T, also called "module" or "crosstie spacing".

According to the invention, the attachment device 1 substan tially comprises a shoulder element 2, a lever element 3, a screw element 5 and, possibly, an insulating plate 4.

In the embodiment illustrated in fig. 1, the shoulder element 2 exemplifyingly consists of a single piece of malleable cast iron (without this being to be considered a limiting factor).

In particular, the shoulder element 2 comprises a small base plaque 2a having a square or rectangular section, of a height at least equal to the sum of the height of foot Rl of rail R and of the relative insulating plate G arranged between the rail and the railroad tie.

On the upper side of the base plate 2a a recess 2b is pre ferably provided, for example with an inverted frustoconical con figuration, the bottom surface of which is shaped to house an end of a stem body of screw element 5. According to a peculiar feature of the invention, on one side of the base plate 2a meant to be arranged adjacent to rail R, a U-shaped element 2c projects upright, better visible in fig. 4A. As represented in said last picture, the U-shaped element 2c substantially has two vertical constraint arms and an upper tran sversal rod, but embodiments may also be provided wherein the U- shaped element 2c is of a different shape and section (for example a single vertical arm and an upper transversal rod.

What is important is that the U-shaped element 2c defines at least a rigid transversal rod integral with the shoulder element 2, kept fixed at a certain height from the upper surface of the base plate 2a, and an underlying window wherein lever element 3 may be easily inserted, as will be better described further on.

Moreover, it is provided that the shoulder element 2 be integral, for example built integrally, with a holding spike 2d, which extends orthogonally from the bottom of the base plate 2a. The holding spike 2d is meant to be embedded and fastened into railroad tie T, in order to provide a stable anchoring of the attachment device 1 of the present invention with railroad tie T. For example, holding spike 2d is in the shape of an embedded element which is integrated into the railroad tie during the ma nufacturing thereof (for example if obtained from a concrete cast), or it is a spike to be engaged in various ways into an insert embedded in the railroad tie.

Preferably, holding spike 2d is arranged in correspondence of the central axis of recess 2b. The holding spike 2d can also be centred on the centre of gravity of the base plate 2a or in another position. Possibly, base plate 2a can have two or more holding spikes 2d.

As can be easily understood with reference to fig. 1, the shoulder element 2 is installed on railroad tie T so that the base plate 2a has a rectilinear side which abuts, possibly with the arrangement in between of insulating plate 4, with the edge of the foot R1 of rail R, so as to act indeed as side constraint shoulder.

Therefore, the shoulder element 2 has the double function of making up a side containment abutment of the rail (with the pro vided gauge) and anchoring of the attachment device 1 to railroad tie T.

According to a preferred embodiment, the shoulder element 2 is provided with a base plate 2a with an adjustable attitude, for example rotatable on an eccentric axis or movable through a shaped eyelet within a constraint pin or other. Such design has the object of being able to change the distance between the rectili near abutment side and the standard anchoring position in the railroad tie: thereby, it is possible to adapt the device 1 to the rail gauge, without changing a standard fastening point the reof to railroad tie T or without having to prepare different pieces for the various gauges.

Lever element 3, in the embodiment shown in detail in figs. 3A-3D, comprises a ring 3a, of an oblong shape and circular sec tion, and a nut 3b locked onto the ring in correspondence of the central opening of ring 3a. Nut 3b has a threading axis X-X ar ranged orthogonally to the lying plane of ring 3a and substan tially on the longitudinal symmetry plane of ring 3a. For example, nut 3b may be formed separately and then joined to ring 3a, for example by means of welding, partly embedded with its walls in a seat suitably obtained on the inner sides of ring 3a. In such case, it is not ruled out that the two pieces be of different metal material, for example steel ring 3a and cast iron nut 3b.

Nut 3b has an inner hole with a thread of nut screw, to suitably engage with a corresponding threaded stem 5b of screw element 5. Finally, nut 3b has outside a normally hexagonal sec tion, but it is not ruled out that it may have a configuration of a different outline, for example a square, octagonal or circular one.

Alternatively, it is provided that the section of the ring 3a may have a different configuration from the circular one, for example I-shaped, triangular, square, rectangular, hexagonal, oc tagonal, and so on. Preferably, the ring 3a of the lever element 3 and the U-shaped element 2c of the shoulder element 2 have the same section. It is understood that this embodiment is preferred because it is obtainable by means of welding of standard components, such as an oval steel ring and a threaded nut, but lever element 3 might also be manufactured in another way, for example in a single suitably forged piece or as described further on. What is impor tant is that elongated lever element 3 be arranged with a proximal end provided with a threaded hole, for the engagement of screw 5, and a distal end which acts as support, between which a suffi ciently sturdy portion be provided to withstand the lever stres ses, as will be better illustrated further on.

The longitudinal extension of ring 3a is hence such that the distance between the thread axis X-X and a distal end 3a' be greater than the distance between the centre of recess 2b and the transversal rod of U-shaped element 2c of shoulder element 2. Therefore, the length of ring 3a is such that, once the symmetry axis of nut 3b is aligned with the centre of the recess 2b of base plate 2a, the distal portion 3a' of ring 3a is located well beyond U-shaped element 2c, as shown in fig. 1.

Moreover, the maximum width of said ring 3a is smaller than the crosswise dimension of the window defined by the U-shaped element 2c of base plate 2a, so as to be easily apt to freely slide within.

Preferably, ring 3a is made of a metal, for example steel, which has an adequate elastic coefficient, in order to suitably absorb the vibrations transmitted by rail R upon the passing of the railway train.

Finally, insulating plate 4 consists of a small metal sheet, preferably of steel, bent into an L-shape. Insulating plate 4 thus has a foot portion 4a, meant to rest above the foot R1 of rail R, as well as a web portion 4b, which is arranged in between and locked between the side of foot R1 and the constraint side of base plate 2a.

According to the non-limiting variant illustrated in figs. 1-4, the length of foot portion 4a is slightly longer than the length of the web portion 4b, so that, once insulating plate 4 has been placed into position, foot portion 4a may reach the splint plane R3 of rail R and define a larger support area of the distal end of lever 3.

The length of web portion 4b is about the same or smaller than the sum of the height of foot R1 and any insulating plate G.

Finally, screw element 5 comprises a bolt or a conventional clamping head 5a and a threaded stem 5b apt to couple with the threaded hole of nut 3b of lever element 3. Preferably, the end of threaded stem 5b is blunt or rounded, to achieve a better support in the recess 2b of base plate 2a.

Figs. 2A and 2B illustrate clearly the operation of the attachment assembly of the present invention.

As can be seen, the rail is arranged between the two shoulder elements 2 (in figs. 2A and 2B one only is shown), in turn pre viously fastened to railroad tie T by inserting the spike 2d embedded in the thickness of the railroad tie, possibly also in serting the two insulating plates 4 into the gap formed between foot R1 and the lateral abutment side of base plate 2a.

Subsequently, lever element 3 is placed parallel to the upper surface of base plate 2a, introducing the distal end 3a' below U- shaped element 2c, until bringing it resting above insulating plate 4 or directly in contact with foot R1. In this condition, threading axis X-X of nut 3b is aligned with the center of recess 2b. Finally, screw element 5 is screwed into the female screw of nut 3b, simply using a classic railroad tie-screw driver which acts on the head 5a of said screw element 5.

In this mounting condition, a class-1 lever is thus deter mined (see fig. 2A) between the resting position of the distal end 3a' of lever 3, which falls onto an axis P-P, a fulcrum position which is located on an axis F-F in correspondence of the transversal rod of U-shaped element 2c, and the force application position, which is ideally placed on the threading axis X-X along which the clamping force applied onto screw 5 expresses itself.

The progressive clamping of screw 5 in the female screw of nut 3a - the end of stem 5b abutting on the bottom of recess 2b - causes a relative sliding of the nut along stem 5b, with a pro gressive moving away of the proximal end of lever 3 from base plate 2a. Since the distal end 3a' rests on the foot portion 4a of the insulating plate, the lever element performs a rotation according to a circle C-C schematised in fig. 2B. When lever element 3 ends in abutment below the transversal rod of U-shaped element 2c, the further infinitesimal rotation of lever element 3 - due to the further clamping of screw 5 - determines the pro gressive increase of the clamping force applied by lever 3 onto insulating plate 4 and hence of foot R1 towards the railroad tie.

Therefore, once lever element 3 is in abutment against U- shaped element 2c, proceeding with the screwing, the clamping torque applied to screw element 5 causes the end of lever element 3 to impart a significant clamping pressure on foot R1 against railroad tie T.

As is understandable, the clamping action of screw 5 trans lates into an advantageous axial pressure action, not only due to the favourable female screw/nut coupling, but due to the further amplification due to a lever effect guaranteed by lever element


As is evident, therefore, the configuration of the attach ment device 1 of the present invention is favourable from a number of points of view: the small number of components, the construc tion simplicity of the same and the favourable lever effect which it is possible to exploit, resulting in an advantageous effect onto the reduced energy used in the installation and on the reduced necessary maintenance.

In particular, unlike the conventional rigid attachment as semblies, for example of the K type, no screw engagements are used directly on the rail stop, where vibrations reach the threaded portion, easily causing the loosening and/or the yielding of the threading.

Hence, it is understood that the design of the attachment assembly of the present invention, in particular the size and the arrangement of lever element 3 and of U-shaped element 2c of shoulder element 2, is such that, by means of a modest torque applied to lever element 5, due to the lever ratio, it determines a remarkable pressure force onto the foot R1 of rail R, in the order of tens of kN.

Moreover, lever 3a has such an elastic coefficient that, despite in the presence of strong vibrations transmitted on the distal end 3a' in contact with the insulating plate, no signifi cant vibrations are transferred to screw 5, with benefits regar ding the fatigue life of the pieces and smaller risks of loosening of the railway equipment.

Moreover, the structure of the attachment device 1 of the present invention allows the cutting of the paths of the vibra tional waves directed towards the threaded portion. As a matter of fact, the vibro-acoustic disturbances - transmitted by rail R to the distal end 3a' of the ring 3a in contact with insulation plate 4 - are mostly transmitted to U-shaped element 2c, which dampen part of the vibrational energy towards the underlying base plate 2a, in order to then discharge onto the railroad tie, redu cing the component which is transferred to screw 5.

It is hence understood that such a solution determines high advantages in connection with the service duration of the attachment assembly.

In figs. 5-9 a second exemplifying embodiment of the inven tion is illustrated.

In this case, a base plate 12a (see figs. 6-6C) is defined by a planar element, provided with a recess 12b and with a slit 12a'. A U-shaped element 12c is defined as a separate piece and is fastened by means of anchoring means 12c' directly to railroad tie T, for example being partly embedded (see figs. 9A and 9B).

Therefore, railroad tie T is supplied already provided with pairs of opposite U-shaped elements 12c and subsequently base plates 12a are engaged with U-shaped elements 12c, causing said U-shaped elements to go through slits 12a'.

Moreover, in figs. 7-8C, another variant of the lever element is illustrated. In this case a lever body 13a shaped with a metal wire or ribbon is provided, so as to define a head with a hexagonal perimeter, with which a nut 13b provided with two opposite flanges 13b' is engaged. As indicated above, nut 13b may be joined by welding to lever body 13a. However, it is understood that the invention must not be considered limited to the particular arrangements illustrated above, which make up only exemplifying embodiments thereof, but that various variants are possible, all within the reach of a person skilled in the field, without departing from the scope of protection of the invention, which is only defined by the follo wing claims.

For example, despite U-shaped element 2c is shown in the shape of an upturned U, it is not ruled out that it may have another shape, for example of an upturned L or T-shaped, provided it allows to define a fulcrum element for lever 3 and a corre sponding passage or window for the passage of lever element 3 which engages with the fulcrum element.

Again, although the holding action of the device may be due mainly to the elasticity of lever element 3 or 13, it is not ruled out to be able to exploit the elasticity typical of other elements, for example the elasticity of the U-shaped element and/or of gauge determination plate 2a.

An alternative embodiment of the invention may also provide that in place of screw 5 some other kind of biasing element is provided, nevertheless suitable to impart a holding force onto the proximal portion of the lever. A wedge-shaped element could for example be provided, in turn actuated by a screw/nut drive or engaged in position by means of elastic elements.

In a further embodiment, the base plate is so arranged as to be able to be displaced and locked onto the railroad tie in dif ferent positions, at different distances from the rail.