The fixing and correct positioning of the seats in automotive vehicles are generally carried out by means of assemblies formed by two parts, the first one being a metal profile that slides longitudinally along lubricated ball bearings over the second one, also a metallic profile. Said parts, fixed to the seat and to the floor by means of screws, which behave concomitantly as interconnected sliding rails, which are hereinafter referred to as respectively upper rail and lower rail.
These sliding rails show cutouts for the seat of the cogs of a position lock which ensures fixation of the assembly in a given position, keeping it unchanged for preservation of the occupants' physical integrity in the event of an impact. Said lock, which the user activates by a lever, through a movement transfer mechanism maintains the chosen locking position until the longitudinal movement of the assembly is released.
However, in the current state of the art, this type of device is still too massive and heavy, presenting flaws such as: the ball bearings arrangement relative to the rail contact surface, which is improperly positioned thereon, thereby generating excessively high lateral loads that result in the accentuated wear of the roller tracks, a fact that is responsible not only for the deterioration of the track but also because of the increased rolling resistance when the seat is moved forward or backward; the activation mechanism of the position lock is generally disposed externally, causing the lever to occupy a larger space close to the rails.
These faults, in which the angle defined by the ball bearing arrangement in the models currently produced by the industry is the major drawback because it allows most of the vertical loading applied onto the rails to be discharged laterally exposing them to premature wear, are further emphasized by the fact that the rail sliding is normally limited by stops contained in the rail structure, requiring a differentiation in the way of accommodation of the profiles so as not to absorb an extra function that often detracts from its ideal performance, because the addition of extra mass causes, in certain cases, a decreased mechanical resistance of the assembly.