TECHNICAL FIELD
[0001] The invention relates to systems for fixing pulleys to a plastic rail of a window
regulator and for fixing the whole window regulator to the metallic structure of a
vehicle door.
STATE OF THE ART
[0002] It is known in the art to mount a pulley to the metallic rail of a window regulator
by means of bolts or studs such that the pulley is axially fixed but can rotate around
the bolt. Sometimes these bolts comprise an annular groove where the edges of the
fixing hole of the rail get trapped supporting the axial forces. Then the rail with
the pulley, cable and other elements is fixed to structure of a vehicle. The problem
is that the pulling forces exerted by the driving cable upon the pulley are transmitted
to the rail in the mounting point of the pulley and the rail is not able to support
them. For reducing the force applied to the metallic rail in the point where the pulley
is mounted is known to attach the rail to the metallic structure of the vehicle in
the point of attachment of the pulley, sometimes with the same bolt or stud used to
mount the pulley to the rail. With that attachment the forces generated by the driving
cable are supported by the structure instead of the rail. Another problem is that
the rotational movement of the driving cable around the pulley applies a torque to
the bolt which can produce a rotation of the bolt in relation to the rail. For that
reason the bolts or studs comprise ribs or protrusions that apply a friction force
to the rail.
[0003] A solution of this kind is shown in
EP-1078170-B1. This invention relates to a stud and a method for mounting a pulley on a metal rail
or plate, for example for window regulators for the automotive industry. According
to this invention, using a cold forming tool, the metal rail is pushed down until
it abuts a shoulder of the stud and the upper portion of the stud is deformed pushing
the edges of the hole of the metal plate into a groove of the stud such that the stud
is firmly fitted into the metal plate thus preventing the axial movement of the stud
and consequently of the pulley in relation to the metal plate. The assembly of the
metal rail and pulley can be mounted in a vehicle door shell by passing the threaded
shaft of the stud through a hole in the door shell and securing the assembly by threading
a nut to the shaft.
[0004] A problem arises when using plastic rails for reducing the weight of the window regulator
because the rail cannot be deformed as described in the patent and what is more important
the plastic material of the rail cannot bear the axial forces exerted by the bolt.
[0005] Another problem is the lack of space inside the vehicle door, specially for housing
the threaded shaft required for fixing the stud to the metallic structure of the door
shell. This lack of space difficulties the mounting of the pulley and possibilities
the window pane being damaged by the edge of the threaded shaft.
DESCRIPTION OF THE INVENTION
[0006] A first aspect of the invention relates to an assembly for a window regulator comprising
a pulley with an axial hole, a plastic rail with a through hole for the fixation of
the pulley and a bolt for fixing the pulley to the plastic rail in an axial direction
but allowing the rotation of the pulley around the bolt. In accordance with the invention
the bolt comprises:
a foot with a diameter smaller than the diameter of the through hole of the plastic
rail and smaller than the diameter of the axial hole of the pulley;
a head with a diameter greater than the diameter of the axial hole of the pulley holding
the pulley in the axial direction;
a shank with a diameter smaller than the diameter of the axial hole of the pulley
such that the pulley can rotate around the shank, but greater than the diameter of
the hole of the plastic rail (in the operation of mounting the assembly, when introducing
the bolt in the axial direction through the axial bore in the pulley and through the
hole of the plastic rail, the shank passes through the axial bore of the pulley but
cannot pass through the hole of the plastic rail) the shank comprising an annular
flat base (a base orthogonal to the axial direction of the bolt such that when introducing
the bolt in the axial direction through the hole of the plastic rail the support base
of the shank rests on a first side of the plastic rail);
a shoulder with a diameter smaller than the diameter of the shank but greater than
the diameter of the foot and smaller than the diameter of the through hole of the
plastic rail, the shoulder comprising a support base; and
an annular groove between the foot and the support base of the shoulder, with a diameter
smaller than the diameter of the foot (for preventing the bolt from moving in the
axial direction in relation to the plastic rail as explained later).
[0007] The foot comprises a threaded axial hole, where a fixing screw can be threaded, as
explained later in more detail. In some embodiments the axial hole of the foot is
a through hole passing through shoulder, shank and head of the bolt. In alternative
embodiments the axial hole extends only partially through the bolt.
[0008] According to the invention an axial length of the shoulder is smaller or equal to
a thickness of the plastic rail (in an area surrounding the through hole of the plastic
rail), such that the annular flat base of the shank rests on a first side of the plastic
rail and the support base of the shoulder is aligned with a second side of the plastic
rail, opposite to the first side (the shoulder remains housed inside the through hole
of the plastic rail).
[0009] The assembly of the invention further comprises a metal sheet with a central hole
with a final diameter smaller than the diameter of the shoulder such that the metal
sheet abuts against the support base of the shoulder. The final diameter of the central
hole is smaller than the diameter of the foot and is fitted in the annular groove.
Thus the metal sheet cannot move axially in relation to the bolt. The center hole
of the metal sheet has an initial diameter greater than the diameter of the foot such
that the metal sheet can be introduced through the foot to mount the assembly of the
invention but, applying a pressing force to the metal sheet, the metal sheet deforms
and expands radially such that the final diameter of the center hole becomes smaller
than the diameter of the foot. That means that the metal sheet has an initial diameter
which permits the assembly of the metal sheet and the bolt and a final diameter, once
assembled, which guarantees that the metal sheet cannot move in relation to the bolt.
[0010] The metal sheet has a minimum radial length greater than the diameter of the through
hole of the plastic rail such that the plastic rail is fitted between the metal sheet
and the annular flat base of the shank. The radial length defines the distance between
the center of the central hole and the exterior border of the metal sheet and the
minimum radial length being greater that the diameter of the hole guarantees that
the exterior border or perimeter of the metal sheet abuts upon the plastic rail outside
the through hole. Thus, the plastic rail is sandwiched between the bolt and metal
sheet and cannot move in axial direction in relation to the bolt. As the metal sheet
cannot move axially in relation to the bolt, the assembly assures a mechanical linkage
in the axial direction. Furthermore, the shape (shape of the exterior border) of the
metal sheet matches a corresponding shape in the second side of the plastic rail,
in an area surrounding the through hole, such that the rotation of the metal sheet
is impeded. The shape of the metal sheet and plastic rail are designed such that when
the metal sheets tries to rotate, the metal sheet collides with the plastic rail.
[0011] In some embodiments the assembly further comprises a recess in the second side of
the plastic rail, surrounding the through hole, for housing the metal sheet. The internal
shape of the recess being a non-circular shape and the metal sheet having a non-circular
shape. Non-circular shape means any polygonal shape such as triangular, square, rectangular,
hexagonal or even an elliptic or ovoid shape. In some alternative embodiments the
metal sheet is mounted, in the recess, eccentric with the hole of the plastic rail.
In that case the metal sheet and the recess can be circular shaped but mounted eccentrically
so that the metal sheet cannot rotate inside de recess. In alternative embodiments
the metal sheet comprises at least a hole fitted in a protrusion in the second side
of the plastic rail. Thus, the metal sheet cannot rotate around the bolt.
[0012] The metal sheet can comprise at least a lateral wing retained in a hole or protrusion
of the plastic rail to improve the retention to the rotational movement of the metal
sheet. The lateral wing can also improve the resistance of the rail to the efforts
exerted on it.
[0013] In some embodiments the support base of the shoulder comprises at least an axial
protrusion which is pressed against the metal sheet such that the bolt cannot rotate
around the foot in relation to the plastic rail. The protrusions can comprise ribs,
facets, toothed elements, studs or any other kind of elements that produce or increase
in the friction force between the bolt and the metal sheet.
[0014] A second aspect of the invention relates to an assembly further comprising a vehicle
metallic structure and a fixing screw threadable in the axial hole of the foot for
fixing the plastic rail and pulley to the metallic structure.
[0015] A further aspect of the invention relates to a method for mounting (fixing) a pulley
of a window regulator to a plastic rail comprising the steps of:
- a) providing a through hole in the plastic rail;
- b) placing the pulley over a first side of the plastic rail with an axial hole of
the pulley aligned with the through hole of the plastic rail;
- c) providing a bolt comprising
a foot with a diameter smaller than the diameter of the through hole of the plastic
rail and comprising a threaded axial hole;
a shank with a diameter smaller than the diameter of the axial hole of the pulley
such that the pulley can rotate around the shank, but greater than the diameter of
the hole of the plastic rail, and comprising an annular flat base;
a shoulder with a diameter smaller than the diameter of the shank but greater than
the diameter of the foot and smaller than the diameter of the through hole of the
plastic rail, the shoulder comprising a support base (orthogonal to the longitudinal
axis of the bolt) and having an axial length smaller or equal to a thickness of the
plastic rail (in an area surrounding the through hole of the plastic rail);
an annular groove, between the foot and the support base of the shoulder, with a diameter
smaller than the diameter of the foot; and
a head with a diameter greater than the diameter of the axial hole of the pulley to
hold the pulley in the axial direction;
- d) providing a metal sheet with a minimum radial length greater than diameter of the
through hole of the plastic rail and a central hole with an initial diameter smaller
than the diameter of the shoulder and greater than the diameter of the foot and wherein
the shape of the metal sheet matches a corresponding shape in the second side of the
plastic rail (in an area surrounding the through hole of the plastic rail) to prevent
the rotation of the metal sheet;
- e) introducing the bolt through the axial hole in the pulley and through hole of the
plastic rail until the annular flat base of the shank rests upon a first side of the
plastic rail whilst the shoulder of the bolt remains housed inside the hole of the
plastic rail and the support base of the shoulder remains aligned with a second side
of the plastic rail, opposite to the first side;
- f) inserting the metal sheet through the foot of the bolt until the metal sheet contacts
partially with the support base of the shoulder and partially with the second side
of the plastic rail;
- g) using a suitable pressing tool, applying pressure between the head of the bolt
and the metal sheet (such that the metal sheet is compressed between the pressing
tool and the support base of the shoulder) to deform the metal sheet such that a final
diameter of the center hole of the metal sheet becomes smaller than the diameter of
the foot and an edge of the hole of the metal sheet gets fitted in the annular groove
of the bolt. At the same time (an outer part of the metal sheet presses the plastic
rail against the annular flat base of the shank) the plastic rail gets firmly fitted
(sandwiched) between the metal sheet and the annular flat base of the shank. Thus
the metal sheet, bolt and plastic rail are fixed therebetween, preventing the bolt
from moving in the axial direction in relation to the plastic rail.
[0016] In some embodiments the method comprises providing on the second side of the plastic
rail a recess where the metal sheet is housed in steps f) (and g), the internal shape
of the recess being a non-circular shape and the metal sheet being non circular shaped
or mounted eccentric with the hole of the plastic rail, to prevent the metal sheet
from rotating around the bolt. In alternative embodiments the method comprises providing
a metal sheet comprising at least a hole which is fitted in step f) (and g) in a protrusion
in the second side of the plastic rail to prevent the metal sheet from rotating around
the bolt.
[0017] The method can comprise providing a metal sheet with at least a lateral wing which
is folded and retained in steps f) (and g) in a hole or protrusion of the plastic
rail.
[0018] In some embodiments of the invention the method comprises providing axial protuberances
(ribs) in the support base of the shoulder of the bolt which are pressed in step g)
against the metal sheet to prevent the bolt from rotating around the foot.
[0019] Another aspect of the invention relates to a method further comprising (after step
g) the step of introducing a screw through a hole in a metallic structure of a vehicle
and threading the screw in the axial hole of the foot, thus fixing the assembly constituted
by the pulley and plastic rail to the metallic structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] To complete the description and in order to provide for a better understanding of
the invention, a set of drawings is provided. Said drawings form an integral part
of the description and illustrate an embodiment of the invention, which should not
be interpreted as restricting the scope of the invention, but just as an example of
how the invention can be carried out. The drawings comprise the following figures:
Figure 1 is an exploded cross section of all the elements of the fixing assembly of
the invention.
Figure 2 is a cross section of the pulley, bolt and metal sheet of the invention mounted
on a plastic rail.
Figure 3 is an enlarged cross section of the bolt and metal sheet, showing anti-rotating
protuberances in the bolt.
Figure 4 shows the step of fixing the assembly of pulley and plastic rail to a metallic
structure of a vehicle. A first embodiment of the bolt is shown.
Figure 5 is a representation similar to figure 4 but with a second embodiment of the
bolt.
Figure 6 is a perspective of a rail with a pulley mounted, seen from the first side
of the rail.
Figure 7 is a perspective of a rail with a pulley mounted, seen from the second side
of the rail.
DESCRIPTION OF A WAY OF CARRYING OUT THE INVENTION
[0021] Figure 1 shows an exploded view of the assembly according to the invention which
comprises:
- A plastic rail 1 with a through hole 11 with a diameter Dr, an a recess 12;
- A pulley 2 with an axial hole 21 with a diameter Dp;
- A bolt 3 comprising a head 31 with a diameter Dh, a shank 32 with a diameter Ds, a
shoulder 33 with a diameter Dsh, a foot 34 with a diameter Df, an annular groove 35
with a diameter Dag, and a threaded axial hole 341;
- A metal sheet 4 with central hole 41 with an initial diameter Dmsi and a final diameter
Dmsf, Dmsi being greater than Dmsf. After cold pressing the metal sheet 4 can expand
and the initial diameter Dmsi of the central hole becomes a final diameter Dmsf smaller
than Dmsi;
- A screw 5.
[0022] As can be seen in figure 1 Dh>Ds>Dsh>Df>Dag. Dh is greater than Dp so that when the
bolt 3 is introduced through the axial hole 21 of the pulley 2 the head 31 blocks
the movement of the pulley 2 in the axial direction, but the pulley can rotate around
the shank 32 because Ds is (slightly) smaller than Dp. This can be seen in figure
2.
[0023] Dsh is smaller than Ds so that an annular flat base 321 (orthogonal to the axis direction
of the shaft) is formed between them and such that, when the bolt 3 is introduced
through the hole 11 of the plastic rail 1, the annular flat base 321 of the shank
32 rests upon a first surface (the upper surface as represented in figure 2) of the
plastic rail 1 and prevents the bolt 3 from passing completely through the hole 11
of the plastic rail 1.
[0024] Df is smaller than Dsh so that a support base 331 (orthogonal to the axis direction
of the shaft) is formed between them and the axial length L of the shoulder 33 is
equal to the thickness W of the plastic rail 1 such that, when the bolt 3 is introduced
through the hole 11 of the plastic rail 1, the support base 331 of the shoulder 33
is aligned with a second surface (the bottom surface as represented in figure 2) of
the plastic rail 1, opposite to the first surface.
[0025] Dmsi is greater than Df but smaller than Dsh, such that when inserting the metal
sheet 4 through the foot 34 (which is already introduced in the hole 11 of the plastic
rail 1) the metal sheet 4 partially contacts with the support base 331 of the shoulder
33 and partially with the plastic rail 1.
[0026] The metal sheet 4 shown in figure 7 has a non-circular external shape such that the
metal sheet 4 fits in the recess 12 of the second side of the plastic rail 1 and prevents
the metal sheet 4 from rotating around the bolt 3. In figure 7 the external shape
of the metal sheet 4 is hexagonal and the recess 12 is also hexagonal. Obviously,
the shape of the metal sheet 4 can be square, pentagonal, octagonal or any other non-circular
shape as long as the recess 12 has a similar shape in which the metal sheet 4 fits
without possibility of rotating.
[0027] Dag is smaller than Df and smaller than Dmsi but when a pressing force is applied
between the head 31 and the metal sheet 4, a radial deformation (expansion) of the
metal sheet 4 will provoke that the edges of the hole 41 of the metal sheet 4 enter
into the annular groove 35 thus preventing the axial movement of the bolt 3 (the diameter
of the central hole is reduced such that the final diameter Dmsf of the center hole
is smaller than Df). At the same time, as shown in figures 2 and 3, the plastic rail
1 gets firmly fitted between the outermost part of the metal sheet 4 and the annular
flat base 321 of the shank 32.
[0028] As shown in figure 3, the support base 331 of the shoulder 33 comprises ribs 332
which are pressed against the metal sheet 4 preventing the rotation of the metal sheet
4 in relation to the bolt 3.
[0029] A screw 5, threadable in the axial hole (341) of the foot (34), permits the fixing
of the assembly (rail 1, pulley 2, bolt 3 and metal sheet 4) to a metallic structure
6 of a vehicle door.
[0030] According to the invention the mounting steps will be as follows:
- a) placing the pulley 2 over a first side of the plastic rail 1 with the axial hole
21 of the pulley aligned with the through hole 11 of the plastic rail 1;
- b) introducing the bolt 3 through the axial hole 21 and through hole 11 until the
annular flat base 321 of the shank 32 collides and rests upon the first side of the
plastic rail 1 whilst the shoulder 33 remains housed inside the through hole 11 and
the support base 331 of the shoulder 33 remains aligned with the second side of the
plastic rail 1.The foot 34 protrudes from the second side of the plastic rail 1 opposite
to the first side;
- c) inserting the metal sheet 4 through the foot 34 of the bolt 3 until the metal sheet
4 is placed inside the recess 12 of the plastic rail 1, remaining the metal sheet
4 partially in contact with the support base 331 of the shoulder 33 of the bolt 3
and partially in contact with the second side of the plastic rail 1;
- d) using a suitable pressing tool, applying pressure between the head 31 of the bolt
3 and the metal sheet 4 to deform the metal sheet 4 pushing the edges of the hole
41 of the metal sheet 4 into the annular groove 35 of the bolt 3. Simultaneously the
plastic rail 1 gets compressed between the metal sheet 4 and the annular flat base
321 of the shank 32. Thus, metal sheet 4, plastic rail 1, and bolt 3 (and pulley 2)
are firmly fixed between them with no possibility of relative axial movement.
[0031] As a result of the mounting process, an assembly as shown in figures 2 or 6 is obtained.
[0032] Further, the assembly obtained in step d) can be attached to a metallic structure
(for example of a vehicle door) by means of a screw 5, threaded in the axial hole
(341) of the foot (34), as shown in figures 4 or 5.
[0033] In this text, the term "comprises" and its derivations (such as "comprising", etc.)
should not be understood in an excluding sense, that is, these terms should not be
interpreted as excluding the possibility that what is described and defined may include
further elements, steps, etc.
[0034] On the other hand, the invention is obviously not limited to the specific embodiment(s)
described herein, but also encompasses any variations that may be considered by any
person skilled in the art (for example, as regards the choice of materials, dimensions,
components, configuration, etc.), within the general scope of the invention as defined
in the claims.
1. Assembly for a window regulator of a vehicle comprising
a plastic rail (1) with a through hole (11);
a pulley (2) with an axial hole (21);
a bolt (3) for fixing the pulley (2) to the through hole (11) of the plastic rail
(1) in an axial direction but allowing the rotation of the pulley (2) around the bolt
(3),
the bolt (3) comprising
a foot (34) with a diameter Df smaller than the diameter Dr of the through hole (11)
of the plastic rail (1) and smaller than the diameter Dp of the axial hole (21) of
the pulley (2), the foot (34) comprising a threaded axial hole (341);
a head (31) with a diameter Dh greater than the diameter Dp of the axial hole (21)
of the pulley (2) holding the pulley (2) in the axial direction;
a shank (32) with a diameter Ds smaller than the diameter Dp of the axial hole (21)
of the pulley (2) such that the pulley (2) can rotate around the shank (32), but greater
than the diameter Dr of the hole (11) of the plastic rail (1), the shank (32) comprising
an annular flat base (321);
a shoulder (33) with a diameter Dsh smaller than the diameter Ds of the shank (32)
but greater than the diameter of the foot (34) and smaller than the diameter Dr of
the through hole of the plastic rail (1), the shoulder (33) comprising a support base
(331) and
an annular groove (35), between the foot (34) and the support base (331) of shoulder
(34), with a diameter Dag smaller than the diameter Df of the foot (34),
characterized in that an axial length L of the shoulder (33) is smaller or equal to a thickness W of the
plastic rail (1), such that the annular flat base (321) of the shank (32) rests on
a first side of the plastic rail (1) and the support base (331) of the shoulder (33)
is aligned with a second side of the plastic rail (1), opposite to the first side,
and wherein the assembly further comprises
a metal sheet (4) with a minimum radial length R greater than the diameter Dr of the
through hole (11) of the plastic rail (1) such that the plastic rail (1) is fitted
between the metal sheet (4) and the annular flat base (321) of the shank (32),
the metal sheet (4) having a central hole (41) with a final diameter Dmsf smaller
than the diameter Dsh of the shoulder (33) such that the metal sheet (4) abuts against
the support base (331) of the shoulder (33), the final diameter Dmsf of the central
hole (41) being smaller than the diameter Df of the foot (34) such that the metal
sheet (4) is fitted in the annular groove (35)
and wherein the shape of the metal sheet (4) matches a corresponding shape surrounding
the through hole (11) in the second side of the plastic rail (1), such that the rotation
of the metal sheet (4) is impeded.
2. Assembly as in claim 1 wherein the plastic rail (1) comprises a recess (12) in the
second side of the plastic rail (1), surrounding the through hole (11), for housing
the metal sheet (4), the internal shape of the recess (12) being a non-circular shape.
3. Assembly as in claim 1 wherein the plastic rail (1) comprises a recess (12) in the
second side of the plastic rail (1), surrounding the through hole (11), for housing
the metal sheet (4), the metal sheet (4) being mounted eccentric with the hole (11)
of the plastic rail (1).
4. Assembly as in claim 1 wherein the metal sheet comprises at least a hole fitted in
a protrusion in the second side of the plastic rail (1).
5. Assembly as in any of previous claims wherein the metal sheet (4) comprises at least
a lateral wing retained in a hole or protrusion of the plastic rail (1).
6. Assembly as in any of previous claims, wherein the support base (331) of the shoulder
(33) comprises at least an axial protrusion (332) which is pressed against the metal
sheet (4) to prevent the bolt (3) from rotating around the foot (34).
7. Assembly as in previous claims further comprising a vehicle metallic structure (6)
and a screw (5) connectable to the threaded axial hole (341) of the foot (34) for
fixing the plastic rail (1) and pulley (2) to the metallic structure (6).
8. Assembly as in previous claims wherein the axial hole (341) passes through the shoulder
(33), the shank (32) and the head (31).
9. Method for mounting a pulley (2) of a window regulator to a plastic rail (1) comprising
the steps of:
a) providing a through hole (11) in the plastic rail (1);
b) placing the pulley (2) over a first side of the plastic rail (1) with the axial
hole (21) of the pulley (2) aligned with the through hole (11) of the plastic rail
(1);
c) providing a bolt (3) comprising
a foot (34) with a diameter Df smaller than the diameter Dr of the through hole (11)
of the plastic rail (1), the foot (34) comprising a threaded axial hole (341);
a shank (32) with a diameter Ds smaller than the diameter Dp of the axial hole (21)
of the pulley (2) such that the pulley (2) can rotate around the shank (32), but greater
than the diameter Dr of the hole (11) of the plastic rail (1) and comprising an annular
flat base (321);
a shoulder (33) with a diameter Dsh smaller than the diameter Ds of the shank (32)
but greater than the diameter Df of the foot (34) and smaller than the diameter Dr
of the through hole (11) of the plastic rail (1), the shoulder (33) comprising a support
base (331) and having an axial length L smaller or equal to a thickness W of the plastic
rail (1);
a annular groove (35), between the foot (34) and the support base (331) of shoulder
(33), with a diameter Dag smaller than the diameter Df of the foot (34) and
a head (31) with a diameter Dh greater than the diameter Dp of the axial hole (21)
of the pulley (2) to hold the pulley (2) in the axial direction;
d) providing a metal sheet (4) with a minimum radial length R greater than diameter
Dr of the through hole (11) of the plastic rail (1), the metal sheet (4) comprising
a central hole (41) with an initial diameter Dmsi smaller than the diameter Dsh of
the shoulder (33) and greater than the diameter Df of the foot (34) and wherein the
shape of the metal sheet (4) matches a corresponding shape, surrounding the through
hole (11), in the second side of the plastic rail (1) to prevent the rotation of the
metal sheet (4);
e) introducing the bolt (3) through the axial hole (21) in the pulley (2) and through
hole (11) of the plastic rail (1) until the annular flat base (321) of the shank (32)
rests upon a first side of the plastic rail (1) whilst the shoulder (33) of the bolt
(3) remains housed inside the through hole (11) of the plastic rail (1), and the support
base (331) of the shoulder (33) remains aligned with a second side of the plastic
rail (1), opposite to the first side;
f) inserting the center hole (41) of the metal sheet (4) through the foot (34) of
the bolt (3) until the metal sheet (4) contacts partially with the support base (331)
of the shoulder (33) and partially with the second side of the plastic rail (1);
g) using a suitable pressing tool, applying pressure between the head (31) of the
bolt (3) and the metal sheet (4) to deform the metal sheet (4) such that a final diameter
Dmsf of central hole (41) becomes smaller than the diameter Df of the foot (34) and
an edge of the hole (41) of the metal sheet (4) gets fitted in the annular groove
(35) of the bolt (3) and the plastic rail (1) gets firmly fitted between the metal
sheet (4) and the annular flat base (321) of the shank (32).
10. Method as in claim 9, further comprising providing a recces (12), surrounding the
through hole (11), on the second side of the plastic rail (1), where the metal sheet
(4) is housed in step f), the internal shape of the recess (12) being a non-circular
shape and the metal sheet (4) being non circular shaped.
11. Method as in claim 9, further comprising providing a recces (12), surrounding the
through hole (11), on the second side of the plastic rail (1), where the metal sheet
(4) is housed in step f), the metal sheet (4) being mounted eccentric with the hole
(11) of the plastic rail (1), to prevent the metal sheet (4) from rotating around
the bolt (3).
12. Method as in claim 9, comprising providing a metal sheet comprising at least a hole
which is fitted in step f) in a protrusion in the second side of the plastic rail
(1) to prevent the metal sheet (4) from rotating around the bolt (3).
13. Method as in any of previous claims 9-12 comprising providing a metal sheet (4) with
at least a lateral wing which is folded and retained in step f) in a hole or protrusion
of the plastic rail (1).
14. Method as in any of previous claims 9-13 further comprising providing axial protuberances
(332) in the support base (331) of the shoulder (33) of the bolt (3) which are pressed
against the metal sheet (4) in step g), to prevent the bolt (3) from rotating around
the foot (34).
15. Method as in any of previous claims 9-14 comprising a further step of introducing
a screw (5) through a hole in a metallic structure (6) of a vehicle and threading
the screw (5) in the axial hole (341) of the foot (34) thus fixing the assembly constituted
by the pulley (2) and plastic rail (1) to the metallic structure (6).