Seat for vehicles having an engagement edge

A seat for vehicles, in particular motor vehicles, with separate backrest and seat base, includes a seat base and a backrest. The seat base is separate from the backrest, and the seat base is constrained to the backrest so that the backrest base can rotate relative to the seat base. The seat base and backrest are each manufactured as one piece of metallic material in a single cold-molding process. At least one of the seat base and backrest includes an engagement edge configured for engaging, via mechanical interference, with a cover for the seat in order to retain the cover.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage Application of International Application No. PCT/IB2017/055794, filed 25 Sep. 2017, which claims benefit of Ser. No. 102017000054500, filed 19 May 2017 in Italy and Serial No. 102016000096583, filed 27 Sep. 2016 in Italy and which applications are incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above disclosed applications.

DESCRIPTION

Technical Field

The present invention relates to the field of seat for vehicles; in particular, it relates to a seat for vehicles with separate backrest and seat base, for terrestrial, naval, aircraft and/or railway applications.

Background Art

Seats for motor vehicles are known which are made as one piece. Such seats are typically intended for sports cars and are manufactured by injection of plastic materials and/or by using aramid fibres (e.g. carbon fibre or Kevlar).

U.S. Pat. No. 6,036,266 to Lear Corporation teaches, for example, that the seat may comprise carbon fibre, magnesium, fibreglass materials or other plastic materials.

As far as seats for road vehicles are concerned, document U.S. Pat. No. 4,147,336 to Toyota illustrates a seat frame wherein multiple seat parts can be molded together, so as to increase the productivity of the manufacturing company.

It is also known that seats for road vehicles must comply with regulations concerning their impact resistance and bearable force, especially when the vehicle in which they are installed collides with fixed objects.

In particular, seats for road vehicles comprise at least two distinct main components:a seat base; anda backrest;

which may possibly be complemented with additional components for more adjustment options and better comfort (such as, for example, recliners, seat lifters, active headrests, sliding guides, lumbar adjustment devices, climate control, and more).

Such seats typically have a metal frame assembled in a number of processing steps.

More in detail, the seat base is assembled from four distinct main parts: two opposite longitudinal members and two opposite transversal members. Such members, after they been welded together (typically in an automated process using robots, and with multiple spot welding or CO2 welding), form, in a plan view, a substantially rectangular structure, to which the seat backrest is then attached. The backrest also requires multiple processing steps to be fully assembled; such steps comprise at least the mutual positioning of transversal reinforcement beams and vertical supporting beams, followed by a number of distinct welding steps.

A known seat backrest is illustrated in US 2006/0138830; the document shows a vehicular seat backrest, wherein a reinforcement structure is bolted to the backrest frame. The backrest also incorporates fastening plates for further constraining the reinforcement structure to the frame.

The seats for road vehicles known in the art suffer from a few drawbacks. In particular, many molds need to be fabricated for making the various seat components, and only at a later stage the seat base and the backrest can be finally assembled.

Not least, those parts which allow supporting the user's body must then be fastened to the seat base. Typically these consist of a framework suspended on springs anchored to the two opposite longitudinal members and/or the two opposite transversal members.

This process is time-consuming and economically inefficient.

The presence of welds or other equivalent fastening means (screws and bolts, as in US 2006/0138830) creates critical points where the fastening means may fortuitously loosen or detach, resulting in seat malfunctions or, even worse, seat failures.

A partial solution to this problem is provided by Italian patent application no. TO2009A000354 by Proma S.p.A., wherein the seat base and the backrest are each manufactured as one piece of metallic material in a single cold-molding process.

However, in order to secure the cover and the padding to the backrest or to the seat base it is necessary to use fastening means created after the seat has been produced, e.g. brackets mounted on the seat base and on the backrest, whereon the cover and the padding can then be attached.

This task is disadvantageous because it leads to longer production times and increases the number of parts that need to be manufactured in order to obtain the seat.

Summary of the Invention

It is one object of the present invention to provide a seat for vehicles which can overcome this and other drawbacks of the prior art, while at the same time being simple and economical to manufacture.

According to the present invention, this and other objects are achieved through a seat for vehicles.

It is to be understood that the appended claims are an integral part of the technical teachings provided in the following detailed description of the invention.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the Figures shown herein by way of example, numeral1designates as a whole a seat for vehicles with separate backrest and seat base, which can be installed in vehicles, such as terrestrial vehicles, in particular cars, or boats, aircraft or railway vehicles.

Seat1comprises a seat base2and a backrest3, wherein seat base2is separate from backrest3, and wherein seat base2is constrained to backrest3so that it can rotate relative to it2. Seat base2and backrest3are each manufactured as one piece of metallic material in a single cold-molding process.

At least one of seat base2and backrest3comprises an engagement edge20,30configured for engaging, via mechanical interference, with a seat cover8of said seat1in order to retain said seat cover8. Therefore, also engagement edge20,30is made from metallic material in a single cold-molding process as one piece with seat base2or, respectively, with backrest3. Preferably, both seat base2and backrest3comprise a respective engagement edge20,30.

When seat1is installed in the vehicle, the user can adjust its tilting angle via known means. Seat1further comprises seatings for the application of means for lifting the seat or sliding it in a direction substantially parallel to the longitudinal development of the vehicle. Said lifting or sliding mechanisms can be made by using any type of cold-molded metal.

More in detail, said metallic material is preferably high-tensile steel such as, by way of non-limiting example, FeE-34, FE P04 or DOCOL 600 DL; in particular, said three types of steel ensure optimal response in terms of strength and energy absorption during a collision. The seat according to the present invention cannot be manufactured from metallic materials that are easily subject to fracture, such as, for example, magnesium, because they react to high stresses with plastic deformation or breakage, as opposed to elastic deformation.

Seat base2and backrest3are each made as one piece in a single processing step. In particular, seat base2and backrest3are preferably manufactured by using the following cold-molding method.

In a first step, a planar steel sheet, defined on a first axis X and a second axis Y, is sheared. During this first step, in particular, central lightening holes2aare created in seat base2, along with optional side holes for the installation of any accessories.

In the first embodiment of seat1described and illustrated herein by way of example, central holes2ain seat base2are circular in shape. Of course, central holes2ashown herein may change in number and shape so that, while lightening seat base2, they can still ensure optimal stress distribution and comfort.

During the first processing step, central lightening holes3aare also created in backrest3, along with optional side holes for attaching any accessories. As described in the previous paragraph, also central holes3ain backrest3may change in number and shape compared to the illustrations provided herein; more in detail, their number and position will affect the weight and the stress response of backrest3.

Subsequently, in a second processing step, the steel sheet perforated during the previous step is deep-drawn. During this processing step, seat base2and backrest3switch from a planar shape to a shape having bends also along a third axis Z distinct from the two axes X, Y that define the steel sheet plane.

Finally, in a third processing step the steel sheet of seat base2and backrest3is bent sideways, so that they will both take their final shape.

A step is also carried out for forming an engagement edge20,30on the steel sheet, configured for engaging, via mechanical interference, with a cover8for said seat1in order to retain said cover8. In particular, engagement edge20,30is made during the deep-drawing step.

As shown inFIG. 1, after the above-described processing steps seat base2will show a recess2bbetween two side walls2cextending at the sides thereof. At the end of recess2b, a front portion of seat base2comprises a front edge20awhich is lower than engagement edges20of side walls2c, so as to form an ergonomic support for the thighs of the user of seat1. Front edge20ais also an engagement edge, in this example joined with engagement edges20of side walls2c, thus creating a continuous profile of said engagement edge20. Front part2dof the bottom wall of seat base2is convex upwards. Front part2dends at front edge20a. Recess2bincludes central holes2a, which are useful for making seat base2lighter.

Optionally, it is possible to make side holes in seat base2for attaching any external components useful for improving the comfort of the seat when in use; by way of non-limiting example, they can be used for securing the height and tilting adjustment controls of backrest3, or the controls for sliding seat1along guides4fastened to the vehicle.

At this point, seat base2is ready for being coated with the cover, e.g. a layer of fabric, leather or velvet covering a padding9; the latter is useful for improving the seating comfort, in particular in the area of recess2b.

Backrest3is processed in the same way as described for seat base2. At the end of the production cycle, backrest3will have a respective pair of containment walls3cextending perpendicular to a bottom region that comprises central holes3a(two in this example); containment walls3c, opposite to each other on both sides of the bottom region, allow limiting the movements of a user's back, especially when the vehicle in which seats1is to be installed is subjected to lateral acceleration loads (e.g. when bending).

When in use, the bottom region will remain substantially parallel to the user's back; in this bottom region, central holes3awill give some flexibility to backrest3, while lightening it without adversely affecting its strength.

Preferably, engagement edge20,30is located in a perimetric position on seat base2and/or on backrest3. Engagement edge30of backrest3is located between the front face and the rear face of backrest3. With reference to the illustrated example, engagement edge30of backrest3is a continuous profile that extends between the two side walls3c, passing through the upper part of backrest3(in this example, the headrest area).

In particular, the backrest3comprises an upper portion6forming a headrest. In the preferred example illustrated herein, upper portion6includes engagement edge30along its outer perimeter. As shown in the drawing, upper portion6defines a cavity suitable for receiving a padding9for the headrest. Then, padding9is housed in the cavity, and cover8is attached to and kept under tension between engagement edges30.

In particular, engagement edge20,30has a recess25or a protrusion for connecting to cover8, and possibly also to padding9, via a male/female system. Therefore, engagement edge20,30has a recess25or a protrusion configured for engaging with a complementary protrusion or recess of cover8.

The seat shown inFIG. 2is finished and coated with a cover8. In particular, cover8of backrest3comprises two net inserts10matching central holes3a.

In the illustrated examples, engagement edge20,30is adapted to engage with and retain cover8. In this manner, cover8will remain under tension in the correct position when seat1is in use. Preferably, cover8includes and engagement portion (e.g. stitched thereto) adapted to mechanically engage with engagement edge20,30. With reference toFIGS. 4, 5 and 8, engagement edge30has a curved shape that creates a recess25, into which a hem of cover8is inserted. In this example, also padding9encircles engagement edge30. InFIG. 4, padding9ends at inserts10; on the contrary, where there is no insert10(see sectional view inFIG. 5), padding9is interposed between backrest3and cover8. Likewise, with reference toFIGS. 6 and 7, engagement edge20has a curved shape that creates a recess25, into which a hem of cover8is inserted and fixed.

By way of example, cover8and padding9may already be joined together (e.g. by stitching or gluing) before being mounted on seat1. The engagement portion of cover8may be either integral with cover8or associable with and removable from cover8.

Therefore, in accordance with a preferred aspect of the invention, an additional processing step is included for mounting cover8on seat base2and/or backrest3by mechanically constraining cover8to engagement edge20,30.

With particular reference to the variant illustrated inFIG. 2, cover8only covers the front part of backrest3, and the metal of the rear part of backrest3remains exposed.

In accordance with an alternative variant, backrest3is wrapped in the cover up to central hole3a. In accordance with a preferred variant, there is at least one central hole3a, in particular two central holes3a.

Optionally, in central hole3aa box can be mounted (e.g. through a snap coupling), which may conveniently be made of plastic, facing towards the rear side of the seat.

With reference toFIG. 8, engagement edge20,30defines, with reference to a cross-section thereof, a recess25and comprises an outer surface having a radius of curvature of at least 2.5 mm with no sharp edges. The outer surface is that surface which faces outwards from recess25, i.e. exposed towards the passenger compartment of the vehicle. The outer surface is rounded or smoothed, and may include flat portions. In this manner, the outer surface has no sharp corners or surfaces, and improves the safety of the users when they are in the vehicle, because the outer surface cannot cause injuries or damage to the user hitting the outer surface of engagement edge20,30, e.g. during an accident or sudden braking. Moreover, thanks to the present invention, it is not necessary to apply any protection elements to the outside of the seat in order to reduce the impact force against the seat, which elements, in addition to being unpleasant to see, would lead to higher production costs and times.

Preferably, the radius of curvature of the outer surface is at least 5 mm, at least in the headrest region. The longer radius of curvature in that region provides higher safety because it allows reducing the impact against the user's head, which is a particularly important body part. It is therefore possible to have different radii of curvature of the outer surfaces in the different regions of engagement edge20,30. For example, in the headrest region the radius of curvature is at least 5 mm, whereas in the other regions it is at least 2.5 mm. As an alternative, the radius of curvature is constant, e.g. at least 5 mm.

In accordance with one possible variant, the radius of curvature is at least 3.2 mm. Such a radius of curvature may be constant along the edge profile. As an alternative, in the headrest region the radius of curvature is at least 5 mm, whereas in the other regions it is at least 3.2 mm.

Optionally, the radius of curvature is variable along engagement edge20,30. Engagement edge20,30is continuous and includes joined sections having different radii of curvature. For example, in the headrest region there is a section having a radius of curvature of at least 5 mm, while in the other sections the radius of curvature is at least 2.5 mm. As an alternative, engagement edge20,30comprises separate sections, each section having a respective radius of curvature, e.g. at least 2.5 mm and at least 5 mm. In any case, engagement edge20,30is made as one piece with backrest3and/or with seat base2, as previously described.

Therefore, the present invention allows manufacturing a one-piece seat that can comply with the current regulations for vehicles, in particularly the one known as ECE Regulation no. 17.

Preferably, engagement edge20,30comprises, with reference to the cross-section thereof, an aperture27that is narrower than recess25, for inserting into recess25an engagement portion associable with cover8. The engagement portion of the cover is thus retained mechanically in recess25by narrower portion27, so that the cover can be stretched around the seat. The engagement portion of cover8conveniently has a shape that is complementary to that of recess25, and is adapted to fit into said recess25through narrower portion27by undergoing a deformation, typically an elastic one. This makes for a simple and quick installation.

With reference to the preferred variant illustrated herein, engagement edge20,30is a sheet steel section having an inner surface facing towards recess25and its outer surface facing outwards.

In particular, in a sectional view engagement edge20,30has a hook-like shape. More in particular, it comprises:a substantially straight first portion21in a position proximal to seat1(in particular, proximal to backrest3or to seat base2, according to the case),a curved second portion22connected to the first portion,a substantially straight third portion23connected to the second portion22,a curved terminal portion24connected to the third portion23.

The two portions22,24are concave towards recess25. In particular, with reference to the non-limiting example ofFIG. 8, the various elements have the following geometric characteristics: the first portion21is at least 20 mm long; the second and fourth portions22have a radius of curvature R2, R4of approximately 5 mm; the length of the third portion23is approx. L3=18.5 mm; the length of the terminal portion24is approx. L4=5.5 mm; the width of recess25is approx. L2=14 mm; the width of narrower portion27is approx. L7=8 mm.

Advantageously, with reference toFIG. 1, along the profile of central hole3athere is a respective engagement edge30a. It is thus possible to constrain cover8to backrest3also at central hole3a, as previously described with reference to engagement edges20,30. Cover8on central hole3amay even be different from the one covering the other parts of seat1.

Engagement edge20,30,30ais made as one piece with backrest3and/or with seat base2, as previously described, and can receive any type of cover8, thus allowing different kinds of saddling without requiring any additional parts.

As aforementioned, in accordance with some possible variants of the invention, seat base2and/or backrest3expose part of the metal, and can therefore have a pleasant shape without jeopardizing the users' safety. For example, the exposed part of seat base2and/or of backrest3may be painted in the same colour as the car, or in a different colour, or be coated with decorative films.

Therefore, the present invention provides a seat that allows for easy installation of the cover on said seat, thereby reducing the seat production times and costs. In particular, it is possible to reduce the number of parts that needs to be mounted to the seat, after the latter has been manufactured by molding, in order to mount the cover. In addition, the seat is lighter.

Of course, without prejudice to the principle of the invention, the forms of embodiment and the implementation details may be extensively varied from those described and illustrated herein by way of non-limiting example, without however departing from the scope of the invention.