Seat belt buckle for road and racing vehicles

Abstract

A seatbelt buckle (10, fig.1) comprising a housing (23, fig.2) having peripheral slots (27, 28, fig.2) receiving tongues (20, 21, fig.1) of seatbelts (1, 2, 3, 4, fig.1), a lock and release mechanism

Description

Technical field The present invention pertains to the field of seat belts for racing and road vehicles and relates, in particular, to a buckle of the so-called ■‘rotational” type, having a mechanism with a rotatable lever control for releasing tongues connected to different straps of the seat belt. Prior art As is well known, in motor vehicles seat belts are provided which are anchored, directly or indirectly, to the body of the motor vehicle. Seat belts are used to hold the driver against the seat in the event of sudden deceleration. In racing vehicles and some road vehicles, the various straps of the seat belt serve to immobilize the driver’s shoulders, pelvis, and legs. The different straps of the seat belt may be connected to each other at a single point, generally placed in front of the torso and at the height of the driver’s pelvis, by means of a buckle, which allows the simultaneous engagement and disengagement of the tongues arranged at the ends of the straps of the belt. To release the tongues, a rotatable lever control member is actuated, which causes a plurality of movable latches or pins to simultaneously disengage from a corresponding plurality of tongues. For each tongue, the buckle is provided with a respective ejector slider which, associated with an elastic element, facilitates the ejection of the tongue from the buckle. Seat belts (so-called “push” type) are known, which are used on non-racing motor vehicles, with a buckle equipped with a button for releasing a single tongue. The buckle is equipped with an ejector slider on which a magnetic element is mounted, which operatively faces a Hall effect sensor installed in the buckle. When the tongue is released, the ejector slider is in a position such that the Hall effect sensor does not detect the proximity of the magnetic element, and in response to this, automatically generates an audible and visual alert, also known as SBR (seat belt reminder). Summary It is an object of the present invention to provide racing-type seat belts equipped with an effective and economical SBR alert system. Another object of the invention is to provide a simplified seat belt by optimizing the number of its components. These and other objects and benefits are achieved, according to the present invention, by a buckle and seat belt having the features set forth in the appended claims. In summary, a buckle for a seat belt, particularly for racing and road vehicles, comprises a housing having a plurality of peripheral slots, each suitable to receive a respective tongue that is attachable to at least one strap of the belt, and a lock and release mechanism for releasably retaining at least one of the tongues; said mechanism comprises at least one releasable latch suitable to releasably retain one of said tongues, and a rotatable lever control member suitable to cause the release of the releasable latch. 'Ilie mechanism also comprises at least one ejector slider movable tn a radial direction within the housing and biased toward a respective lateral slot by an associated elastic element to exert a thru st in a radially outward direction and to facilitate the ejection of a tongue when said mechanism is actuated to release said at least one tongue. The buckle comprises a Hall effect sensor and an associated printed circuit board housed in a concave base of the housing and a radially movable magnetic element integral with the ejector slider and operatively facing said sensor. Brief description of the drawings The features and advantages of the buckle and seat belt according to the present invention will be apparent from the following description, given by way of example and not limitation. Reference is made to the appended drawings, in which: Fig. 1 is an overall schematic view of a four-point seat belt with a buckle according to an embodiment of the present invention, in an open condition, with the tongues unlocked from the buckle; Fig. 2 is an exploded perspective view of the buckle in Fig. 1; Fig. 3 is a partial perspective view in longitudinal section of the buckle of Fig. 2 with the tongue inserted and locked in the buckle; Fig. 4 is a partial perspective view in longitudinal section of the buckle of Fig. 3 with the tongue disengaged from the buckle; and Fig. 5 is a partial perspective view, at an enlarged scale, of some of the buckle components. Detailed description Referring to the drawings (Fig. 1), a seat belt, particularly for sports cars or other racing vehicles, comprises a buckle 10 of the type known as a "roiaw buckle” and a plurality of belt straps, for example four belt straps 1, 2, 3, 4. Each belt strap has a first end part 15, 16, 17, 18 fixable to a stationary point on the car and a second end part 11, 12, 13, 14 attached to a tongue 20, 21, which is suitable to be connected to the buckle 10. In this example there are two tongues, 20, 21. The buckle 10 comprises a housing or outer body 23 (Fig. 2), in this example shaped like a cylindrical drum, defining a central axis A with an inverted cup-shaped upper body 24 and a concave base or lower body 25, rigidly coupled together. The housing 23 defines therein a chamber that houses most of the components of a lock and release mechanism, of a type known per se, which screes to releasably retain the seat belt tongues. The housing has a side surface 26, in this example substantially cylindrical, and a front surface 29, which is orthogonal to the axis A. The side surface 26 of the housing lias a plurality of peripheral slots 27, 28 angularly spaced about the axis A and intended, in use, to receive a respective tongue. Throughout this description and in the claims, terms and expressions indicating positions and orientations such as “longitudinal,” “radial,” “tangential” shall be intended to refer to the central axis and longitudinal axis A. Each tongue 20, 21 comprises a. shaped metal plate having at least one through-slot, advantageously two slots 30, 31 and 32, 33, for the passage of a respective strap of the seat belt, and a th rough-hole 34, 35 defined in a position which in use is radially innermost or central, i.e., closest to the axis A of the buckle. Each through-hole 34, 35 serves to allow the passage of a respective latch or retaining pin 40. In the illustrated example, the two slots in each tongue are elongated in shape in substantially tangential directions relative to the axis A. Advantageously, the two slots on each tongue are adjacent or consecutive in a circumferential direction relative to the axis A. Preferably, the tongues 20, 21 and corresponding seats in the lower body 25 have a differently (or “anti-error’’) shaped profile that makes it impossible for the tongue of one side to be inserted into the opposite side of the buckle or in an upside-down orientation by mistake. The buckle 10 has a lock and release mechanism, of a type known per se, for releasably retaining the tongues of the seat belt. The general design and operating features of-the lock and release mechanism are known per se. The lock and release mechanism comprises at least one releasable latch 40 suitable to releasably retain one of said tongues, and a rotatable lever control member 41 suitable to cause the release of the releasable latch. Tire rotatable release lever 41 is mounted externally- on the front surface 29 of the housing 23 and is rotationally integral with a central shaft 42 and rotatable therewith about the axis A. Hie latches 40 have a stem portion 43 that engages through respective holes 44 of an annularshaped movable plate 45 and through respective holes 46 of an annular-shaped fixed plate 47 integral with the housing 23. The holes 44, 46 formed in the movable plate and in the fixed plate serve as a guide and restraint for the latches 40 and are axially aligned with the respective holes 34, 35 of the tongues when said tongues are inserted into the peripheral slots 27, 28 and remain firmly locked therein by the engagement of the ends of the latches. Single contrast springs 48 are associated with the latches 40 to hold them in a lowered or engaged tongue-locking position. The movable plate 45 has a central tubular formation 50 that receives the rotatable shaft 42 and provides a lower surface that engages with cam surfaces 52 which are integral with the rotatable shaft 42 and extend about the axis A defining inclined surfaces. A central spring 51 keeps the movable plate 45 engaged against the cam surfaces 52. Ilie latches 40 have enlarged heads 53 arranged above the movable plate 45. Due to the effect of the cam surfaces 52, a rotation of the shaft 42, controlled by means of the lever 41, lifts the movable plate 45, in contrast to the elastic action provided by the contrast springs 48, and consequently the disengagement of the latches from the holes of the tongues, which are thus released from the buckle. Each peripheral slot for inserting the tongues is associated with an ejector slider 60, configured to facilitate the exit of the tongue from the buckle after the seat belt has been released. The ejector slider is a slider that is movable in a radial direction inside the housing, and oriented toward a respective lateral slot: each ejector slider is associated with an elastic element 61, in this example a compression spring, suitable to push the ejector slider (and the tongue, if inserted) in a radially outward direction. In the illustrated embodiment (Fig. 3), the ejector slider has an axially prominent portion 62, arranged more centrally or radially inward resulting in a step formation with a tangential or transverse surface 63 suitable to act in a relationship of radially outward thrust against an end surface of the tongue, and a base 64 on which a lateral end surface of the tongue may rest. The ejector slider 60 forms a support portion 65 protruding from below for carrying a magnetic element 66. integral with the ejector slider. 'Ilie support portion with the magnetic element 66 is received in a cavity 67 of the concave base 25 of the housing, wherein a board 68 with a printed circuit board (or PCB) and a transducer or Hall effect sensor 69 is arranged, operatively facing the magnetic element 66 when the seat belt tongue is locked in the buckle. The printed circuit board PCB is connectable, via an electrical cable 70 (Fig. 1). to an electronic control unit (not shown) mounted on board the vehicle. When the seat belt is released (Fig. 4), and the latch 40 is extracted from the hole 34 in the tongue, the ejector slider is free to move and, pushed by the spring 61, moves the tongue in a radially outward direction causing it to be ejected from the buckle. Tire corresponding movement between the magnetic element 66 and die sensor 69 causes the Hall effect sensor’s output voltage and current to vary, resulting in the generation of an electrical signal indicative of the tongue release, or SBR (seat belt reminder) signal indicating an unfastened belt. The number of movable latches is variable depending on the design of the seat belt, in particular the number of belt straps. At least one of the tongues is firmly connected in a manner known per se to a belt strap by means of a fixed latch, analogous to tire movable latches 40 but not operable by the release mechanism. The rotation of the lever 14 thus produces the simultaneous release of all the tongues except one. to which the buckle remains attached. Advantageously, the same tongue may have two slots for two respective belt straps, thus reducing the number of ejectors and their corresponding associated sensors (SBR sensors). In the example of a four-point belt, two tongues may be sufficient, each for an abdominal strap and a shoulder strap. In such a configuration, a single SBR sensor with associated PCB and a single magnetic element cu a single ejector slider may be sufficient. This detail allows two belt straps to be connected or disconnected from the buckle at the same time, while only-releasing one tongue, allowing to thus simplify the system. Various aspects and embodiments of the buckle and seat belt have been described. It is understood that each embodiment may be combined with any other embodiment. Furthermore, tire invention is not limited to the described embodiments, but may be varied within the scope defined by the appended claims.

Claims

1. A buckle for seat belts, tn particular for racing and road vehicles, wherein the buckle comprises:a housing having a plurality of peripheral slots, each suitable to receive a respective tongue that may be attached to at least one belt strap,a lock and release mechanism for releasably restraining at least one of said tabs, the mechanism comprising at least one releasable latch suitable to releasably retain one of said tongues, and a rotatable lever control member suitable to cause the release of the releasable latch, at least one ejector slider movable in a radial direction within the housing and biased toward a respective lateral slot by an associated elastic element to exert a thrust in a radially outward direction and to facilitate the ejection of a tongue when said mechanism is operated to release said at least one tongue;characterized in that the buckle comprises a Hall effect sensor and an associated printed circuit board housed in a concave base of the housing and a radially movable magnetic element integral with the ejector slider and operatively facing said sensor.

2. A buckle according to claim 1, wherein the ejector slider forms a support portion protruding from below, which has the magnetic element, and which is received in a cavity of the concave base of the housing.

3. A seat belt comprising:a buckle according to any of the preceding claims,at least one tongue connected to two belt straps and having two slots for attaching said two respective belt straps, andan electrical cable suitable to connect the printed circuit board with an electronic control unit on board of the vehicle.

4. A seat belt according to claim 3, wherein the seat belt is a four-point belt having two abdominal straps and two shoulder straps and two tongues, of whicha first tongue is connected to a first abdominal branch and a first shoulder strap, and is securely connected to the buckle anda second tongue is connected to a second abdominal strap and a shoulder strap, and is releasably connected to the buckle, and whereinthe buckle is provided with a single ejector slider, a single Hall effect sensor, and a corresponding single magnetic element mounted on the single ejector slider and operatively associated with said single Hall effect sensor.

5. A seat belt according to claim 3 or 4. wherein the two slots are adjacent and consecutive in a circumferential direction relative to a longitudinal axis (A) of the buckle, perpendicular to a geometric plane wherein the tongue extends.

6. A seat belt according to claim 5, wherein the slots are elongated in respective tangential directions relative to said longitudinal axis.

Images