Patent Description:
<CIT> discloses a front-end arrangement for a railway vehicle with an impact structure and a wiper device comprising a motor unit and a front wiper. The impact structure comprises at least one impact absorbing element. The wiper device is attached to the impact structure and is movable relative to a support of the front arrangement and thus movable relative to the supporting structure of the vehicle so as to move backwards in the event of an impact and to enable the effective impact energy to be absorbed by the impact absorption element.

This arrangement, however, fails to address the risk of a wiper motor unit, or any other piece of equipment, piercing a crash-resistant plate that separates the impact absorbing structure of the front end from the driver's cabin or passenger compartment. Another front arrangement for a rail vehicle of the aforesaid kind is known from <CIT>.

The invention aims to provide a front arrangement for a rail vehicle, in which the risk of a piece of equipment piercing through a crash-resistant plate of the front arrangement is reduced.

According to a first aspect of the invention, there is provided a front arrangement for a rail vehicle, comprising a crash-resistant plate having a front side facing a front direction of the front arrangement, a piece of equipment and a bracket assembly for fixing the piece of equipment to the front side of the crash-resistant plate, wherein the bracket assembly includes a frame positioned at a distance from the crash-resistant plate for supporting and fixing the piece of equipment and at least a first bracket-linking the frame to the crash-resistant plate, wherein a front end of the piece of equipment protrudes from the frame in the front direction and a rear end of the piece of equipment protrudes from the frame towards the crash-resistant plate at a distance from the crash-resistant plate, and the first bracket has a first plastically deformable region located at a distance from a reference axis parallel to the front direction and crossing the front end of the piece of equipment, wherein the first plastically deformable region defines a first pivot area, such that a force applied to the front end of the piece of equipment towards the crash-resistant plate parallel to the front direction above a force threshold results in plastic bending of the first plastically deformable region and a pivoting movement of the piece of equipment and frame about the first pivot area. The first plastically deformable region is shaped to allow stress concentration and constitute a preferential deformation zone.

During an impact, the orientation of the piece of equipment relative to the crash-resistant plate changes before the piece of equipment reaches the crash-resistant plate, thereby ensuring the physical integrity of the crash-resistant plate, which cannot be pierced through by a violent backward translation of the sharp rear end of the piece of equipment. If the energy released during the impact is so high that a contact between the side of the piece of equipment and the crash-resistant plate occurs, the area of such a contact is substantially greater than it would be between the plate and the sharp rear end of the piece of equipment, leading to a better distribution of the mechanical stress on the crash-resistant plate, to avoid the piercing of the impact-resistant plate.

In one embodiment, the plastic bending of the first bracket causes the piece of equipment to pivot by at least <NUM>° and preferably at least <NUM>°. The closer the pivoting movement is to a <NUM>° angle, the larger the area of contact between the piece of equipment and the crash-resistant plate, should such contact take place.

In one embodiment, the first bracket has a reduced cross-section in the plastically deformable region compared to the remainder of the first bracket to concentrate stress. More generally, the plastically deformable region has a lower quadratic moment relative to a centroid axis of the first bracket parallel to reference axis than the remainder of the first bracket.

In one embodiment, the first bracket comprises sheet metal with a V-shaped cut-out, the plastically deformable region of the first bracket being located at a vertex of the V-shaped cut-out. The section of the bracket with the lower quadratic moment of area is located at the vertex of the V-shaped cut-out and has the lower resistance to plastic deformation. Therefore, the location of the V-shaped cut-out on the bracket defines the position of the pivot area.

In one embodiment, an end of the first bracket is in surface contact with the front side of the crash-resistant plate. The surface of contact between the first bracket and the front side of the crash-resistant plate is large enough to distribute the load during an impact.

In one embodiment, the end of the first bracket is fixed to the front side of the crash-resistant plate by the means of fixing elements such as screws, bolts, rivets or the like.

In a preferred embodiment, the bracket assembly comprises a second bracket linking the frame to the crash-resistant plate and spaced apart from the first bracket, the second bracket has a second plastically deformable region located at a distance from the reference axis, wherein the second plastically deformable region defines a second pivot area, such that a force applied to the front end of the piece of equipment towards the crash-resistant plate parallel to the front direction above the force threshold results in plastic bending of the first and second brackets and a pivoting movement of the piece of equipment about a pivot axis, wherein the pivot axis crosses the first and second pivot areas and an orthogonal projection on a reference plane perpendicular to the front direction of the front end of the piece of equipment is located at a distance from an orthogonal projection on the reference plane of the pivot axis. The distance between the orthogonal projection on the reference plane of the front end of the piece of equipment and the orthogonal projection on the reference plane of the pivot axis can be adjusted to adjust the global mechanical resistance of the structure to bending. The second plastically deformable region is shaped to allow stress concentration and constitute a preferential deformation zone. In one embodiment, the second bracket has a reduced cross-section in the plastically deformable region compared to the remainder of the first bracket to concentrate stress. More generally, the plastically deformable region has a lower quadratic moment relative to a centroid axis of the first bracket parallel to reference axis than the remainder of the first bracket.

The second bracket is particularly useful to enable the bracket assembly to resist torque about the reference axis, as may occur in particular if the piece of equipment is a wiper motor unit.

In one embodiment, the bracket assembly is made of several parts, which are preferably welded together following welding lines. The parts are preferably made of sheet metal.

In one embodiment, the first, and if applicable the second bracket, include(s) at least one associated reinforcing rib extending from the frame to the crash-resistant plate to ensure that the plastic bending of the bracket takes place as intended, and reduce the risk of unwanted deformations, such as a buckling. In one embodiment, the first and, if applicable, the second bracket, form(s) with the associated reinforcing rib a closed cross-section to withstand high service loads, in particular torsion loads.

In one embodiment, the piece of equipment is a wiper motor unit.

In one embodiment, the front arrangement comprises an outer skin which covers the frame and at least partially covers the piece of equipment and is preferably made of glass-reinforced plastics. Preferably, the front end of the piece of equipment protrudes from the outer skin.

The above-mentioned embodiments can be combined.

Other advantages and features of the invention will then become more clearly apparent from the following description of a specific embodiment of the invention given as non-restrictive example only and represented in the accompanying drawings in which:.

Corresponding reference numerals refer to the same or corresponding parts in each of the figures.

With reference to <FIG>, a front arrangement <NUM> for a rail vehicle comprises a central gangway arranged to allow passengers to move from a first car to a second car connected with the first car and at least one windscreen for a driver located in a driver's cabin at least partly housed in the front arrangement. The front arrangement <NUM> is formed by a body structure covered by an outer skin <NUM>. The outer skin bestows to the head its shape and is made of light material, for instance of GRP (Glass Reinforced Plastics).

With reference to <FIG>, a region Z1 of the front arrangement <NUM> is illustrated with the outer skin <NUM> partially removed, to let appear the body structure of the front arrangement <NUM>, in particular a crash-resistant plate <NUM>, preferably made of thick sheet metal. The crash-resistant plate <NUM> has a front side <NUM> facing a front direction of the front arrangement <NUM>. The front arrangement <NUM> comprises a piece of equipment <NUM> and a bracket assembly <NUM> for fixing the piece of equipment <NUM> to the front side of the crash-resistant plates <NUM>. In this embodiment, the piece of equipment <NUM> is a wiper motor unit, yet any other kind of piece of equipment can be fixed with the bracket assembly <NUM>.

The bracket assembly <NUM> illustrated in <FIG> includes a frame <NUM> positioned at a distance from the crash-resistant plate <NUM> for supporting and fixing the piece of equipment <NUM>. Here, the piece of equipment <NUM> is fixed to the frame by means of fixing elements <NUM> such as screws or bolts. The outer skin <NUM> covers the frame <NUM> and at least partially covers the piece of equipment <NUM>. In this embodiment, the bracket assembly <NUM> comprises a first bracket 42a and a second bracket 42b linking the frame <NUM> to the crash-resistant plate <NUM>. The second bracket 42b is spaced apart from the first bracket 42a. A front end <NUM> of the piece of equipment <NUM>, here a motor shaft, protrudes from the frame <NUM> in the front direction and preferably protrudes from the outer skin <NUM>. A rear end <NUM> of the piece of equipment <NUM> protrudes from the frame <NUM> towards the crash-resistant plate <NUM> at a distance from the crash-resistant plate <NUM>.

The first bracket 42a has a first plastically deformable region R1 which has a lower quadratic moment, and therefore a lower resistance to bending, than a remainder of the first bracket 42a. The second bracket 42b has a second plastically deformable region R2 which has a lower quadratic moment, and therefore a lower resistance to bending than a remainder of the second bracket 42b.

The first and second plastically deformable regions R1, R2 are located at a distance from a reference axis <NUM> which is parallel to the front direction and crosses the front end <NUM> of the piece of equipment. The first plastically deformable region R1 defines a first pivot area 43a and the second plastically deformable region R2 defines a second pivot area 43b such that a force applied to the front end <NUM> of the piece of equipment <NUM> towards the crash-resistant plate <NUM> parallel to the front direction above the force threshold results in plastic bending of the first and second brackets 42a, 42b and a pivoting movement of the piece of equipment about a pivot axis <NUM>, which crosses the first and second pivot areas 43a, 43b. Viewed in a reference plane P perpendicular to the front direction, an orthogonal projection of the front end <NUM> of the piece of equipment <NUM> is located at a distance from an orthogonal projection of the pivot axis <NUM>.

When a force parallel to the reference axis is applied to the front end of the piece of equipment <NUM> during a collision, the plastic bending of the first and second brackets 42a, 42b causes the piece of equipment <NUM> to pivot by at least <NUM>°, and preferably at least <NUM>° about the pivot axis <NUM> before the side of the piece of equipment <NUM> eventually collides with the crash-resistant plate <NUM>.

Claim 1:
A front arrangement (<NUM>) for a rail vehicle, comprising
- a crash-resistant plate (<NUM>) having a front side (<NUM>) facing a front direction of the front arrangement (<NUM>),
- a piece of equipment (<NUM>) and
- a bracket assembly (<NUM>) for fixing the piece of equipment (<NUM>) to the front side (<NUM>) of the crash-resistant plate (<NUM>),
wherein the bracket assembly (<NUM>) includes a frame (<NUM>) positioned at a distance from the crash-resistant plate (<NUM>) for supporting and fixing the piece of equipment (<NUM>) and at least a first bracket (42a) linking the frame (<NUM>) to the crash-resistant plate (<NUM>),
a front end (<NUM>) of the piece of equipment (<NUM>) protrudes from the frame (<NUM>) in the front direction and a rear end (<NUM>) of the piece of equipment (<NUM>) protrudes from the frame (<NUM>) towards the crash-resistant plate (<NUM>) at a distance from the crash-resistant plate (<NUM>), and
the first bracket (42a) has a first plastically deformable region (R1) located at a distance from a reference axis (<NUM>) parallel to the front direction and crossing the front end (<NUM>) of the piece of equipment (<NUM>),
characterised in that the first plastically deformable region (R1) defines a first pivot area (43a), such that a force applied to the front end (<NUM>) of the piece of equipment (<NUM>) towards the crash-resistant plate (<NUM>) parallel to the front direction above a force threshold results in plastic bending of the first plastically deformable region (R1) and a pivoting movement of the piece of equipment (<NUM>) and frame (<NUM>) about the first pivot area (43a).