Seat belt buckle, in particular for racing vehicles

0001The present invention relates to a seat belt buckle, in particular for racing vehicles, to which the following description refers purely by way of example.

0002As is known, regulations require that motor vehicles be equipped with seat belts fitted directly or indirectly to the vehicle body at so-called anchorage points, and for securing the driver to the driver's seat in the event of accidents.

0003In racing vehicles, the various straps of the seat belt are designed to immobilize the driver's shoulders, pelvis, and, possibly, legs, and are connected to one another at a single point, normally located in front of the torso and at the height of the driver's pelvis, by a common buckle enabling simultaneous locking and release of the individual straps.

0004More specifically, the buckle comprises a casing housing a releasable lock mechanism and defining five openings in which to insert and lock respective metal end members (tongues) fixed to the ends of the seat belt straps.

0005The buckle casing is also fitted with a manually operated release lever by which to rapidly release the lock mechanism from the tongues of all the seat belt straps, and so enable the driver, in an emergency, to free himself easily from the seat belt securing him in the driver's seat.

0006<patcit id="pcit0001" dnum="US3747167A"><text>US3747167</text></patcit> discloses a rapid-release buckle for straps of a harness, for example of a parachute or other safety device. The buckle comprises a plurality of locking members and a general actuating device acting on the whole of the locking members so as to withdraw them and release all the straps. A second actuating device is provided, which has an independent control and acts selectively on only some of the locking members so as to withdraw them and release a corresponding selected number of the straps. The two actuating devices are compatible with each other and are connected in series.

0007Current regulations require that the buckle be connected to the various tongues of the seat belt so that the release lever in the rest position faces downwards, i.e. towards the driver's feet.

0008The release lever of most known buckles is sized and shaped to project from the buckle casing to permit relatively easy operation by the driver.

0009Because of the movements of the driver when driving the vehicle, however, the release lever, given its position, may come into contact with the driver's legs, thus resulting in discomfort, and may even be inadvertently released by the driver when driving the vehicle, thus resulting in undesired release of the seat belt and exposure of the driver to grave danger in the event of an accident.

0010It is an object of the present invention to provide a seat belt buckle, in particular for racing vehicles, designed to eliminate the aforementioned drawbacks.

0011According to the present invention, there is provided a seat belt buckle, in particular for racing vehicles, as claimed in Claim 1.

0012A preferred, non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which: <ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">Figure 1</figref> shows a view in perspective of a preferred embodiment of the buckle according to the invention;</li><li><figref idref="f0001">Figure 2</figref> shows a top plan view of a detail in <figref idref="f0001">Figure 1</figref>;</li><li><figref idref="f0001">Figure 3</figref> shows a section along line III-III in <figref idref="f0001">Figure 2</figref>;</li><li><figref idref="f0002">Figure 4</figref> shows a cross section of the <figref idref="f0001">Figure 1</figref> buckle;</li><li><figref idref="f0002">Figure 5</figref> is similar to <figref idref="f0002">Figure 4</figref>, and shows a different section of the buckle in a different operating condition.</li></ul>

0013Number 1 in <figref idref="f0001">Figure 1</figref> indicates a seat belt buckle, in particular for racing vehicles.

0014Buckle 1 comprises a substantially cylindrical casing 2, of axis A, defined by a cup-shaped body 3 and a base 4 connected to each other by screws.

0015Casing 2 comprises a substantially cylindrical lateral surface; and an end surface perpendicular to axis A.

0016The lateral surface defines five slots 5 unequally spaced angularly about axis A, and which are engaged, in use, by respective end members 6 (only one shown) defined by die-cut metal parts and attached to the seat belt straps.

0017Casing 2 houses a known lock mechanism 7 (<figref idref="f0002">Figure 5</figref>) for releasably retaining end members 6 of the seat belt.

0018A release lever 8, connected to lock mechanism 7, is hinged to the end surface to rotate roughly 90° about axis A, and along a path lying in an actuating plane perpendicular to axis A, from a rest position to at least one release position, so as to release lock mechanism 7 simultaneously from all the end members 6 of the seat belt straps.

0019Release lever 8 comprises a plate 9 lying on the end surface and defined by a circular ring 10 hinged to the end surface, and by an arm 11 integral with circular ring 10 and having an end 12 projecting radially from the lateral surface of casing 2 when release lever 8 is rotated about axis A (in a manner not shown).

0020Release lever 8 also comprises a grip appendix 13 projecting from end 12 of arm 11 and extending parallel to axis A, in the opposite direction to the end surface of casing 2, to permit easy grip and operation of release lever 8 by the driver.

0021According to the invention, buckle 1 also comprises an additional safety component 20, shown in detail in <figref idref="f0001">Figures 2 and 3</figref>, for preventing inadvertent operation of release lever 8 when release lever 8 is in the rest position.

0022With reference to <figref idref="f0001">Figures 1 to 3</figref>, additional safety component 20 comprises a lever guard portion 21, which rests on the lateral surface of casing 2 and is substantially half-moon-shaped (<figref idref="f0001">Figure 2</figref>), so that, viewed along axis A, buckle 1 has a substantially ovoid lateral profile with no corners.

0023Lever guard portion 21 is the same thickness as casing 2 along axis A, is positioned contacting plate 9 of release lever 8 in a direction parallel to axis A, and comprises a concave surface complementary to and mating with the lateral surface of casing 2, and a curved convex outer surface blending seamlessly with the lateral surface to avoid corners.

0024As shown particularly in <figref idref="f0001">Figure 1</figref>, an ideal extension of the curved convex outer surface of lever guard portion 21 in a direction parallel to axis A surrounds end 12 of release lever 8 when release lever 8 is in the rest position.

0025Additional safety component 20 also comprises a lock appendix 22 having a hole, and which projects from the concave surface, is substantially the same shape as end members 6 of the seat belt, and engages a slot 5 defined by the lateral surface of casing 2 and indicated by reference number 30 (<figref idref="f0002">Figure 4</figref>).

0026<figref idref="f0002">Figures 4 and 5</figref> show cross sections of buckle 1 in two different planes and in two different operating conditions. More specifically, <figref idref="f0002">Figure 4</figref> shows engagement of lever guard portion 21 of additional safety component 20, and <figref idref="f0002">Figure 5</figref> release of an end member 6 of the seat belt.

0027Lock appendix 22 (<figref idref="f0002">Figure 4</figref>) is retained irreversibly inside slot 30 by a lock device 31 housed in casing 2 and comprising a lock pin 33, which is pushed, in a direction parallel to axis A, into a lock position by a spring 34.

0028One end of lock pin 33 has an inclined surface facing the inlet of slot 30, and which backs up lock pin 33 as lock appendix 22 of additional component 22 is inserted inside slot 30. Once lock appendix 22 is inserted fully inside slot 30, lock pin 33 is pushed by spring 34 so as to click inside the hole in lock appendix 22 and so lock additional component 20 and prevent withdrawal of lock appendix 22 from slot 30.

0029Lock pin 33 is what is known in slang as a "dummy", in that lock device 31, of which it forms part, is distinct from lock mechanism 7 (<figref idref="f0002">Figure 5</figref>) and, in use, is not subject to the release action of release lever 8, so that connection of lever guard portion 21 to casing 2 of buckle 1 is irreversible.

0030With reference to <figref idref="f0002">Figure 5</figref>, to releasably retain each end member 6 of the seat belt, lock mechanism 7 comprises a respective lock pin 36 substantially similar to lock pin 33 in <figref idref="f0002">Figure 4</figref>.

0031Lock pin 36, however, is smaller in height than lock pin 33, so that, when release lever 8 is rotated, an annular projection 37 of lock pin 36 is moved axially by a plate 38 of lock mechanism 7, in opposition to the elastic action of a conical spring 39, to release relative end member 6 of the seat belt. That is, when release lever 8 is rotated as far as it will go, lock pin 36 frees the hole in end member 6, which is expelled from slot 5 by an ejector spring 40 loaded when inserting end member 6.

0032Operation of buckle 1 and additional component 20 will be clear from the foregoing description.

0033The advantages of the buckle according to the present invention will also be clear from the foregoing description.

0034In particular, in normal driving conditions, as opposed to contacting the release lever in the rest position, the driver's legs tend to rest on the convex surface of the lever guard portion, which thus prevents any inadvertent movement of the release lever and, hence, undesired release of the seat belt. Moreover, the buckle is compact and lightweight, which are essential characteristics in racing car applications, by only guarding the release lever in the rest position, i.e. only when necessary.

0035The particular ovoid shape of the buckle, with no projections, and the thickness of the lever guard portion, equal to that of the buckle, produce no discomfort when the buckle comes into contact with the driver's legs, and at the same time permit troublefree voluntary manual operation of the release lever.

0036Finally, the fact that the end of the release lever is positioned directly contacting the lever guard portion prevents accidental insertion of foreign bodies between the lever guard portion and the release lever.

0037Clearly, changes may be made to the buckle as described and illustrated herein without, however, departing from the scope of the present invention as defined in the accompanying Claims.

0038In particular, the lever guard portion may be shaped otherwise than as described and/or be formed in one piece with the buckle casing, with no need for the lock appendix or lock device.