Abstract:
The invention relates to a rod comprising a long plastic body ( 1 ), an axial housing ( 3 ) close to the front end corresponding to the push button ( 2 ), and a compression spring ( 4 ) mounted in said housing ( 3 ), one end of the spring butting up to the front end wall ( 3 ′) of the housing, and the other end of the spring ( 4 ) butting up to a side piece ( 5 ) provided for this purpose on a plastic guiding part ( 6 ) on which the rod ( 1 ) slides during its straight movement, the guiding part ( 6 ) being fixed onto the actuating lever itself. The connection of each part to the traction lever enables the actuation of the handbrake of a motor vehicle.

Description:
OBJECT OF THE INVENTION 
       [0001]    The present invention, as it is expressed in the statement of this specification, relates to an actuating rod for the hand brake of a motor vehicle, envisaged to relate to the traction lever through which the effectiveness or ineffectiveness of the hand brake of the vehicle is established. 
         [0002]    The object of the invention is to significantly reduce the noise that occurs in the actuation of the traction lever of the hand brake on motor vehicles. 
       BACKGROUND OF THE INVENTION 
       [0003]    Currently, in certain types of vehicles the operational or actuating mechanism of the hand brake is constituted from a lever mounted in a swing way with respect to a fixed support anchored in the bodywork of the vehicle, which support is equipped with a toothed sector wherein is interlockable a nail or ratchet belonging to a piece mounted on a rotational way on the own actuating lever and linked by its opposite end to that of the nail to a rod with oscillating rectilinear motion, which is displaceable in the interior of the own lever. The rod is finished up by its anterior end and externally in a push button whereby and against the action of a spring the displacement of the rod is carried out, consequent swing of the carrier piece of the nail or ratchet and the release of this with respect to the toothed sector established in the fixed support, so this release allows to carry out the swing of the lever and corresponding actuation on the hand brake towards the inoperative position of the same, as in the swing in the opposite sense of such lever occurs the actuation of the hand brake towards its operational position, remaining in this position precisely by the interlocking produced of the nail on the toothed sector, since such nail tends to swing towards the interlocking position by the push of the rod into the interior, by the force exerted in that sense by the spring linked to it. 
         [0004]    Well, in this type of mechanism the oscillating rectilinear motion of the rod from the position in which the nail is located on the ridge of a tooth of the toothed sector to the interlocking position, is significant, which leads to a remarkable increase in the compression strength of said spring, with the consequent transmission of force to the nail or ratchet and thereby a significant accumulation of kinetic energy in this, that translates into noise at the impact of the nail on the valley of the corresponding tooth in every interlocking of it on the toothed sector. 
         [0005]    This energy of impact on the nail or ratchet is sent back to the mechanism in the form of vibrations, being returned to the own rod and therefore to the spring, producing effects of resonance with additional noises that are perceived by the user through the handle of the actuation lever, such that the resonance caused by the vibration and noise produced are increased because the rod is metallic and is in contact with metallic elements constitutive of the actuation lever, nail or ratchet piece and toothed sector itself. 
       DESCRIPTION OF THE INVENTION 
       [0006]    The actuating rod object of the invention has been designed to solve the problems and shortcomings referred to in the preceding paragraph. 
         [0007]    Accordingly, the rod in question is characterized primarily by being made in plastic material, and on it is located the corresponding compression spring, causing that it is isolated from the metal parts of the assembly of the mechanism. 
         [0008]    In addition, the rod of the invention, in its straight-ahead slide, is guided on a guide-piece, also plastic, with features in a way such that on one side it embraces a section of the rod and on the other it surrounds the spring to prevent that it slips out from its location or housing established for that purpose in the own rod, allowing it to slide smoothly and without backlashes. 
         [0009]    This guide-piece fits into the corresponding traction or actuation lever, being fixed to it in virtue of that the guide-piece has externally complementary shoulders of entrants provided for this purpose on said lever, to establish the interlocking and fixing of both parts to each other, allowing the sliding of the rod with respect to such guide-piece, when acting on the respective push button envisaged in its anterior or external end. 
         [0010]    On the other hand, it has been envisaged that the rod is provided with a calibrated stop and situated at a determined and optimal distance, which is in contact with the guide-piece with respect to which the rod slides when the set or desired push stroke of the button ends. At that time of stop, the displacement of the rod is blocked forming a compact assembly that does not transmit force to the corresponding nail or ratchet linked to the opposite end of the rod, so that said non-transmission of force is due to that the produced reaction is absorbed by the actuation lever, at the front part close to the push button. 
         [0011]    The linking of the carrier piece of the nail or ratchet at the end of the rod is performed as it is conventional, through a coupling by way of ball joint between both parts, for which at the end of the rod is established a concave grooving on which the arched and flat edge of the carrier piece of the nail or ratchet is positioned and retained, this provided at the opposite end. Said piece of the nail or ratchet is affected with a hole for an articulation pin of the same on the actuation lever of the brake. 
         [0012]    Another feature of novelty of the invention is focused on that the nail or ratchet is distanced from the swing point to a greater extent than the one existing between such swing point and the linkage end or ball joint of the rod, producing a demultiplier effect such that a movement of the tip or end of the nail or ratchet translates into a very small movement in the rod, producing a minimum compression in the spring. 
         [0013]    The teeth of the toothed sector have a geometry such that the angular oscillation of the nail or ratchet is very limited, and that is a result of the reduced distance between the ridge of the teeth and the opposite flank of the adjacent tooth. 
         [0014]    Such feature establishes that the oscillating rectilinear motion of the rod from the position of the nail in the ridge to the interlocking position of such nail is very small compared to the oscillation produced in conventional mechanisms, so the compression of the spring produced by this oscillation is also very small. 
         [0015]    Based on what it has been discussed, the spring will have an initial compression force calibrated to the required force for its use and safe operation of the retention system, since it is compressed with little oscillation load, barely increasing the force when it reaches the point of maximum compression in which the edge of the nail or ratchet and in the ridge of the tooth corresponding to the toothed sector are aligned, keeping almost constant the force applied to the nail. 
         [0016]    Based on this feature or improvement for the invention, is achieved reducing the energy stored in the spring that is transmitted to the nail at the time of triggering thereof, from the ridge of the tooth to the impact against the opposite flank of the teeth of the segment, such that the kinetic energy of the nail at the moment of impact is very small, so the transformation of said energy in noise is lower, and the sound effect is significantly reduced. 
         [0017]    The energy of the nail or ratchet after the impact is returned to the mechanism due to the versatility of materials in the form of vibrations, contrary to what happens in conventional systems where the vibrations return to the rod and thus to the spring. 
         [0018]    Finally, say that the spring in its mounting on the rod is completely isolated from metal parts that are likely to resonate with vibrations, as it has been already mentioned in the section on Background of the invention, which provides a break of the bridge of transmission of vibrations. 
         [0019]    The advantages deriving from the new conception of the rod described with respect to those provided for in conventional systems can be summarized in the following:
       Reduction of the noise of the impact of the nail or ratchet against the toothed segment.   Isolation of the spring against the vibrations produced by the impact of the nail or ratchet-segment, avoiding the resonance of the same.   Reduction of mass of all the components, improving the speed of coupling of the mechanism to reduce the inertia of all moving parts. This effect enhances security when it comes to a bad use of the hand brake by the user, if an untimely deactivation of the brake lever is performed; reducing the time it takes the nail or ratchet to interlock again.   Reduction of costs of production of the actuation assembly of the rod-push button.   Ease of setting of the rod-push button-nail or ratchet assembly.   Substantial improvement of the process due to the decrease in the number of components for the same function.       
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    To complement the description that will be carried out next and with the object of helping to a better understanding of the features of the invention, the present description is accompanied by a set of drawings based on which the innovations and advantages of the actuation rod for the hand brake of vehicle will be more easily understood made in accordance with the object of the invention. 
           [0027]    FIG.  1 .—Shows a view according to a lateral perspective of the rod of the invention and the spring and the guide-piece exploded in a position to be mounted on it. 
           [0028]    FIG.  2 .—Shows an elevational side view of the assembly shown in the previous figure, with all components properly assembled and connected to the rear end of the rod the carrier swing piece of the interlocking nail on the corresponding toothed sector anchored to the chassis of the vehicle. 
           [0029]    FIG.  3 .—Shows an enlarged detail of the shape of the teeth of the toothed sector and the nail itself or interlocking ratchet, as well as the angle of oscillation of such nail or ratchet. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0030]    As it can be seen in the figures referred to above, the rod  1  of the invention consists of an elongated body made of plastic material at the end, considered as anterior, of which includes a push button  2  and in a section more interior to the same a longitudinal housing  3  wherein is housed a spring  4  that is retained between the anterior end  3 ′ of that housing and a pin  5  provided in the front part of a guide-piece  6  mounted on that section of the rod  1  corresponding to the housing  3 , embosoming the same and wrapped around the spring  4  to prevent that this slips out from its housing  3 . 
         [0031]    The guide-piece  5  has a special configuration as it can be seen in  FIG. 1 , and is provided on the outside with shoulders  7  which are complementary of others provided for this purpose on the corresponding actuation lever on which is mounted said rod  1 , so that the latter is axially displaceable by pressing the button  2  with respect to the guide-piece  6 . In this way the spring  4  that is retained in the housing  3 , between the bottom  3 ′ of it and the pin  5  of the piece  6 , does not make contact with any metallic element since the rod  1  as a whole is plastic, as it is the own piece  6 , that spring  4  being isolated from the vibrations that can occur at the impact of the corresponding interlocking nail or ratchet  8  on the toothed sector  16  corresponding to a conventional hand brake, such that said isolation from the vibrations prevents that resonance can be produced as it occurs conventionally. 
         [0032]    The nail or ratchet  8  is provided at the end of a piece  9  with a hole  10  with swivel mounting on the corresponding actuation lever, while the end opposite to the nail or ratchet  8  has an arched conformation, flat on the sides, that fits and establishes the assembling means in a concave housing  12  established in the own end of the rod  1  so the sliding in one way or another of the rod  1 , carries with it the swinging of the piece  9  to establish the interlock or release of the nail or ratchet  8  with respect to the toothed sector  16 . 
         [0033]    The rod  1  and laterally to the housing  3  has a calibrated stop  17  as it is represented in  FIG. 1 , establishing a limit of displacement of such rod  1  with respect to the guide-piece  5 , thus limiting the displacement or push stroke of the button  2 . At that time when the stop  17  makes contact with the guide-piece  6 , the displacement of the rod  1  is blocked, forming a compact block without transmission of force towards the nail or ratchet  8 , since all the reaction is absorbed by the corresponding actuation lever at the front, close to the push button  2 . 
         [0034]    The distance of the nail or ratchet  8  with respect to the swing point established in the hole  10  is longer than the distance between that swing point  10  and the end  11  of attachment to the own rod  1 , giving rise to a demultiplier effect between the end of the nail or ratchet  8  and the articulation with the rod  1 , producing a minimum compression on the spring  4  and therefore a minimization of noise. 
         [0035]    In turn, the teeth of the toothed sector  16  have a special geometry, as it is that of the nail or ratchet  8 , which allow to produce an angular oscillation, indicated by the angle  13  of  FIG. 3 , very small, because the distance existing between the ridge  14  of the teeth corresponding to the toothed sector  16  and the flat area or opposite flank  15  of the adjacent tooth, is very small, as it can be seen clearly in  FIG. 3 . 
         [0036]    That oscillation movement is in turn demultiplied, as stated above, due to the relationship of levers established between the swing point established in the hole  10  and the ends corresponding to that of the linking  11  to the rod  1  and that of the own nail or ratchet  8 , converting the rotary motion into rectilinear, and reducing the effect of noise. 
         [0037]    As it has been already stated previously throughout this specification, the oscillating rectilinear motion of the rod  1  from the position of the nail or ratchet  8  on the ridge  14  to the position of interlock between two teeth of the toothed sector  16 , is very small in comparison with the oscillation produced in conventional actuation systems of the same type, so the compression of the spring  4  produced by said oscillation will be also very small, so the initial compression force of the spring is barely increased when the point of maximum compression is reached, in which the corresponding ridge  14  of the toothed sector  16  and the nail or ratchet  8  are faced as it is represented in  FIG. 3 , all of this getting a reduction of the energy stored in the spring  4 , such that the kinetic energy of the nail or ratchet  8  at the moment of impact will be very small, so the transformation of said energy or noise will be lower, totally reducing the sound effect. 
         [0038]    In addition, that energy after the impact of the nail or ratchet  8  is returned to the mechanism by the elasticity of the materials, the rebound vibration of the nail or ratchet  8  being absorbed by the plastic material of the rod  1 , preventing it from being transferred to the spring and that it resonates, collaborating on this the fact that said spring  4  is completely isolated from metallic pieces susceptible to resonate with vibrations, as conventionally occurs.