Note: Descriptions are shown in the official language in which they were submitted.
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BACXGROUND O~ THE INVENTIO~
The present invention relates to automotive vehicie
bumpers and, more particularly, to a bumper constituted by
a single shaped element of thin sheet steel, havin~ in
S cross-section a substantially "C"-shaped profile which
comprises a web and two flanges.
According to recent safety regulations, bumpers of the
above type must be attached to the vehicle by means of
energy absorbers and must carry, at least on the outer face
of the web, a thick longitudinal cushion of rubber or the
like. Following a bum~ at low speeds, the bumpers must not
undergo permanent defoxmations, that is to say, that the
load applied to them must not exceed the yielding limit of
the metal. This requires that the bumper has a higher
resistance to bending than that of normal "C"-shaped profile
bumpers. A higher resistance to bending can be obtained with
a bumper constituted by a thick shaped element, but the
requirements of lightness necessitate that an element of
this type is produced in a light alloy, with high material
and manufacturing costs.
The problem which is at the heart of the present
invention is that of providing a bumper which presents the
heigh~ened resistance to bending required by the security
regulation-~, but which is at the sam~ time very llght and
economical to manufacture.
According to the present invention, this problem is
resolved by the fact that the web of the bumper presents,
from its external surface, a series of depressions which
form a plurality of ribs.
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Beyond conferring a heightened degree of resistance,
the said depressions have the advantage that between them
there are formed relief spaces which the thick cushion of
rubber or the like, which is normally applied to the external
face of the web, can go to fill when it is compressed by a
bump, and with this is obtained a greater absorption of
the b~mp energy by the covering.
B~IEF DESCRIPTION OF THE DRAWING:
The invention will be more cleariy understood from the
Q 10 description which follo~s of a preferred embodiment, ,
described-with reference to the attached drawing, given by
way of non-limitative example and in which:
Figure 1 is a ~ront view partially in perspectiYe of
a bumper;
Figure 2 is a cross-section taken in the plane
indicated by line II-II of Figure l;
Figure 3 is a view in ~ragmentary perspective, similar
to that of Figure 1, but with a cushion of rubber applied
on the front face of the ~umper;
- Figure 4 is a fragmentary section taken along line
IV-IV o Figure 2;
Figure 5 is a section similar to that of Figure 2, but
taken in a zone of the bumper in which a reinforcing plate
is provided; and,
Figure 6 is a section ta~en along broken line VI-VI
of Figure 5.
DETAILED DESCRIPTION:
Tn Figure 1 there is shown a part substantially correspond-
ing to a half of a bumper according to the invention, which is
30 constitutQd by a single shaped element of thin sheet steel, it
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being understood that the remaining part of this element,
which is not represented, is su~stantially sy~-netrical and in
a sing~e piece with ~he represented part.
T~e bumper presents in a cross-section a substantially
"C"-shaped profile which comprises a web, designated in the
drawings with the numeral 10, and two flanges, designated
in the drawings respectively with the numerals l2 and 14.
The b~nper is shaped in its longitudinal direction so as to
present an arcuate form corresponding substantially to that
of the anterior or posterior part of a vehicle. In Figure 1,
a rect~ngular aperture 16 has also been represented, cut in
the web toward~ one end for the installation of a lighting
.
apparatus and another aperture is symmetrically disposed at
the other end, this not being shown.
According to the inven~ion, the web 10 presents, from
its external surface, a series of depressions 18, o~tained
e.g. by drawing. These depressions can have ~arious forms,
provided that they form a plurality of ribs such as to
increase ~he degree of resistance to bending of the bumper
as a whole. Nevertheless, according to the preferred
embodiment of the invention illustrated in the drawings, each
depression presents a substantially rectangular contour
with two side edges 20 and 22 oriented in the transverse
direction of the bumper and two end edges 24, 26 oriented
in the longitudinal direction of the bumper and is constituted
by a pair of wall parts 28, 30 which symmetrically converge
towaras the interior of the "C"-shaped profile of the bumper
from the respective side edges 20, 22 and of another pair of
wall parts 32, 34 which syn~netrically converge towards the
int~rior of the profile from the respective end edges 24, 26.
Prefera~ly, as shown, the wall parts 32, 34 are directly
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joined a~ ~he bottom of the depression along a line 36.
In the preferr~d embodiment, the contiguous side
edges 20, 22 of ad,acent depressions 18 are connected at a
curved connecting zone 38 which, together with the wall parts
28, 30 form a rib. The b~nper, then, has on the web 10 a
series of ribs parallel to each other and trans~erse to ~e
longitudinal direction of the bumper itself. The embodiment
thus described can also be seen, in cross-section and in
longitudinal section respectively, in Figures 2 and 4, where
the above-m~ntioned parts are designated with the same
reference n~nerals. In particular, in Figure 2 the ;ine 36
of each depression 18 can be seen forming together with the
wall parts 32 and 34 a rib, of small longitudinal dimension,
directed towards the interior of the bumper profile. For a
further increase of the moment of inertia, in the web 10
there is also preferably provided a pair of ribs 40, 42 of
rounded profile, directe~ towards the interior of the "C"-
shaped pxofile of the b~nper and extending along the respecti~e
end edges 24, 26 of the depressions 18. Further, always for
the same reason, the connecting part 44 of the web 10 with
the flange 12 presents in cross-section a profile concave
towaxds the interior or the "C"-shaped pro~ile of the bumper.
A similar profile! can also be provided in the connecting
part of the web 10 with the 1ange 14.
2~ Also ror the reason of increasing resistance to bending,
the free edges 46, 48 of the flanges 12, 14 are turned in
towards the interior of the bumper profile.
~ 5 illustrated in Figure 3, on the external face of the
web 10 ther~ is nor.nally attac~ed for example by means of
screwing~ a thick longitudinal cushion o~ rubber or the like,
of known type, designated by the numeral 50, which extends
along the entire web, ~rom one end to the other of the bumper.
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This cushion 50 presents towards the web 10 a flat surface.
In other words, the covering 50 is applied to the web 10
without pene~rating into the depxessions 18, thus leaving
a cavity between each depressio~ and the cushion 50, as
indicated at 52. For a secure attachmenl-, the cushion 50
presents ho~lever in correspondence with the connecting part
44 an internal surface which exactly conforms to the
external~surface of the part 44.
The presence of the cavities ~2 behind the cushion 50
offers the advaniage that each cavity constitutes a relie~
space into which a part of the cushion 50 can extend~ until
it is completely filled, when the cushion is compressed by a
bump, by which a greater absorption of the energy of the
bump by the cushion itself is obtained with a reduced
possibility of permanent deformation of the bumper.
Referring to ~i~ures 5 and 6, for increasing the total
rigidity of the bumper, in the channel of the "C"-shaped
profile of the bumper, there are fixed reinforcing plates,
such as the one designated with the reference nu~leral 54.
These plates are provided at intexvals along the length of
~he bumper, in its central ~one which is moxe greatly stresse~
in the case of a bump. E.g., three reinforcing plates can
be provided, i.e., a central plate situated in the middle of
the bumper and two other plates situated at a distance o~
the order o 30 cm from the two sides of the central plate.
The plates such as 54, which are preferably of drawn
sheet steel, are disposed in planes transverse to the
lontidutinal direction of the bumper and have an outline
strictly corresponding to that ~f the profile of the bumper
itself.
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As representea in Figure 6, each plate such as 54
presents arou~d the periphery a flange 56 bent at right angles
by means of which it is connected to the internal surface
of the bumper and in particular to the converging wall parts
32, 34 of the depression 18 in correspondence of which it
is situated, and this flange 56 is preferably attached to ~he
bu~per by means o~ spot-welding. In the plate 54 there is
further preferably formed a stiffening rib 58 which advantag-
eously has the form of a "V" with its apex pointed towards
the web 10. For the purpose of lightening, in the plate 54
there are further advantageously provided apertures 60 on
two sides of the rib 58.
As a result o~ the above, according to the invention,
there is therefore produced a bumper which satisfies the
safety regu~ations, but which at the same time, due to small
thickness of the sheet employed is very light. Optimum
results have been obtained with a steel sheet having a
thickness o 2 mm, having a yie}ding load of 30-32 kg/mm2.
In particular, the provision is oreseen o~ the shaped
- 2~ element having reinforcing plates of stainless steel sheet
having the above said characteristics of ~hickness and
resistance. Due to the small thick~ess adopted, the employment
o stainless steei permits lower production costs with respect
to various other types of steel which necessitate chromium
plating.
Naturally, without prejudice to the principle of the
invention, its particular embodiments can be amply variable
with respect to the embodiment illustrated and described,
without going beyond the scope of the invention itsel~.
W3~:po
February 11, 1976
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