Patent Publication Number: US-10329806-B2

Title: Closing device for a motor-vehicle hood, and method

Description:
The invention relates to a latching device for a door or a flap and in particular for a hood of a motor vehicle with a locking mechanism comprising a catch and at least a pawl for latching of the catch. The latching device comprises a drive which moves the locking mechanism in such a way that a door gap or hood gap can be made smaller in the closed state of the door or flap. 
     The purpose of a latch or latching device of the type initially stated is for the temporary closure of openings in motor vehicles or buildings with the aid of doors or flaps. In the closed state of such a latch the catch encompasses a bracket-shaped locking bolt in particular with two arms (known as load arm and collecting arm). In the case of a motor vehicle, the locking bolt can be attached to a door or a flap of the motor vehicle and then the latch to the chassis or vice versa. The present invention is especially advantageous for front hoods or front flaps which are located at the front when viewed in the usual direction of travel of a motor vehicle. 
     Within the scope of the invention, the locking mechanism is regularly installed on the chassis side, is therefore attached to a pertaining motor vehicle chassis. In contrast, the locking bolt is connected to a hood. Consequently, a hood latch or motor hood latch is usually viewed. 
     If the catch of such a latch or latching device reaches a closed position by means of pivoting starting in an open position, the catch is ultimately latched by means of the pawl. Such a pivoting is attained by the locking bolt (also referred to as “latch holder”) when it engages into the catch by closure of a pertaining door or flap. A locking area of the pawl is then adjacent to a locking area of the catch in the latched position, whereby the catch is prevented from being rotated back in the direction of the open position. The locking bolt can no longer leave the locking mechanism in the closed position. 
     For opening it is necessary to move the pawl out of its ratchet position. If the pawl is moved out of its ratchet position, the catch rotates in the direction of the open position. The locking bolt can leave the latch in the open position of the catch and thus in the open position of the locking mechanism. The door or flap can thus be opened again. 
     There are latches with two different ratchet positions of the catch. The catch can then initially be latched in the so-called pre-ratchet position and ultimately in the so-called main ratchet position by further rotation in the direction of the closed position. 
     DE 10 2008 005 181 A1 describes a latching aid to pull a flap or a door of a vehicle towards the motor vehicle chassis. The purpose of the known drive is to also open the door or flap. A combined closure and electrical opening of a tailgate latch arises from the publications DE 100 33 092 A1, DE 10 2004 011 798 B3 and DE 10 2004 013 671 A1. 
     There is an activation device in order to open the latch. If the activation device is activated, the locking mechanism opens. A door handle or flap handle can be part of the activation device. This handle is generally connected to an activation lever of the latch via a rod or a Bowden cable. If the handle is activated, the activation lever of the latch is pivoted in such a way by means of the rod or the Bowden cable that the latch opens. A motor vehicle can demonstrate an external handle which is generally pivotable which can be reached from the outside and/or a generally pivotable internal handle which can be reached from the inside. 
     If a locking mechanism of a motor vehicle is latched by closure of a door or a flap, a gap fundamentally remains between the door or flap and the adjacent chassis. Such a gap should be kept as small as possible especially for hoods located at the front when viewed from the usual direction of travel in order to prevent disadvantageous air turbulence in the front area and associated air resistance during a journey. However, a closed surface which is as gap-free as possible is also desired for optical reasons. 
     The German pre-registration DE 10 2013 109 051 deals with minimization of such gaps on doors or flaps. The known latch is mobile and in particular pivotably located. Following latching of the locking mechanism, the latch is moved or pivoted overall by a drive in such a way that a gap between the door or flap and chassis is minimized. The drive provided for this purpose comprises an electromotor and a pivotable lever which is known as a swing arm. By pivoting of the lever or the swing arm (hereinafter also known as a “swing lever”) by the electromotor the latch overall is pivoted in such a way that the gap is minimized. The latch housing is held by a jack which is pivotably attached to the swing arm. 
     Insofar as not specified otherwise hereinafter, the object of the invention can demonstrate the aforementioned characteristics individually or in any combination. 
     It is the task of the invention to provide a further developed latching device with which a gap in a door or flap can be minimized. A particular objective is to minimize the risk of injuries. 
     In order to solve the task, a latching device encompasses the characteristics of claim  1 . Advantageous designs result from the dependent claims. 
     A latching device for a door or flap demonstrates a locking mechanism comprising a catch and a pawl for latching of the catch. There is a drive with which the locking mechanism can be moved partially or completely using a swing lever, hereinafter also referred to as a swing arm, in such a way that a door gap or flap gap can be made smaller. If the door or flap is therefore closed, a gap initially remains between the door and the doorframe or between a frame and the pertaining flap. By means of the drive the swing arm and thus the locking mechanism or parts thereof can be moved in such a way that this gap decreases. In order to minimize the weight and the number of parts, the catch and the pawl are preferably pivotably attached to the swing arm by means of axes. 
     In one design, a retaining lever is attached to the swing arm to retain the catch and is preferably pivotably attached. This means that the catch can strike the retaining lever during a closure process in order to trigger an impact from the catch into the swing arm. This design contributes to the drive being protected from such impact forces and thus from damage. 
     In one design, the latching device is created in such a way that the pawl can only latch the catch when the catch has been retained by the retaining lever. This design contributes to a door gap or hood gap already being relatively small before the catch is latched. This contributes to preventing injuries due to trapped fingers and such. 
     In one design, the latch is created in such a way that the pawl can only latch the catch after the drive has pivoted the swing arm for reduction of a door gap or hood gap. This contributes to preventing injuries due to trapped fingers and such. 
     In one design, there is a control contour which is capable of pivoting the retaining lever out of its retaining position after the retaining lever has retained the catch. In a technically simple manner, a latch with advantageous characteristics can thus be provided with a small number of parts, which is capable of protecting in particular a drive for gap minimization from impacts and which is created in such a way that the risks of injury due to trapped fingers are prevented. 
     In one design, there is a control contour which is capable of pivoting the retaining lever out of its retaining position by pivoting the swing arm to reduce a door gap or hood gap or flap gap. In a technically simple manner, a latch or a latching device with advantageous characteristics can thus be provided with a small number of parts, which is capable of protecting in particular a drive for gap minimization from impacts and which is created in such a way that the risks of injury due to trapped fingers are prevented. 
     In one design, there is a rod which can be activated by a drive in order to move the pawl into or out of its ratchet position. This design enables suitable pivoting of the pawl. As a drive, a drive is envisaged in particular which is capable of pivoting the swing arm. The number of drives required is thus minimized. Alternatively, a control contour can be provided for with which the movement of the pawl in particular effected by pivoting movements of the swing arm can be suitably controlled. The pawl is in particular pre-tensioned by a spring in such a way that the pawl can be moved into its ratchet position by spring force. 
     In a technically simple design, the drive has a drive disk which is capable of pivoting the swing arm. 
     In one design, the drive disk possesses a protruding bolt, hereinafter also referred to as the first bolt, which restricts rotary movements of the drive disk. In particular, a rotation of the drive disk effects in this design causes the bolt to be moved against a stop in order to suitably limit rotary movements of the drive disk. The first bolt is in particular attached at the edge in order to enable compact construction space. 
     In one design of the invention, the stop for the first bolt is provided by a moving stop and in particular by a pivotably located lever. It is thus possible to enable rotary movements of the drive disk which are up to 360° and more despite the stop. The pivotably located lever preferably demonstrates a T-shaped end in order to act directly as a stop. The first bolt then reaches in particular into an angle of the T-shaped end when the drive disk is rotated as far as possible. There are preferably one or two further stops, for example in the form of bolts, which limit the pivoting movements of the pivotably located lever in order to provide a stop in a particularly reliable manner which is capable of suitably limiting the rotary movements of the drive disk. 
     In one design, the drive disk possesses a protruding bolt, hereinafter referred to as a second bolt, with which pivoting movements of the swing arm can be controlled by being supported. During a latching process, the swing arm is supported on the second bolt and preferably with an arched end. Rotary movements of the drive disk then enable movement of the second bolt. Thus, pivoting of the swing arm is enabled during a latching process for the purpose of making a gap smaller if the swing arm is supported on the second bolt. As the swing arm is only supported, it can be manually pivoted away from the bolt. The door or flap is therefore not closed with the force expended by the drive. Risks of injury are prevented if a finger is then located in the gap of a pertaining door or flap or hood. 
     In one design, a protruding bolt, hereinafter also referred to as a third bolt, is attached to the drive disk which can be moved into an arch-shaped end of the swing arm by rotating the drive disk in order to thus retain and pivot the swing arm. This design determines the position of the swing arm by the position of the bolt during a latching process when the bolt has been moved into the arch-shaped end. Manual movements of the swing arm by pivoting of a door or flap are then no longer possible. The door or flap can then be closed with the force expended by the drive. Thus, for example, against sealing pressure of a door seal or flap seal. 
     In one design of the invention, a pivoting of the swing arm in order to make the gap smaller is initially effected by the aforementioned second bolt and subsequently by the aforementioned third bolt. In a first phase, during making the gap smaller a finger located in the gap can therefore not be further trapped by the drive. Only when the gap has been made sufficiently smaller does the third bolt make the gap smaller and shut the door or flap. 
     In one design of the invention, there is preferably a pivotably attached bracing lever which is capable of bracing the swing arm when an impact is initiated in it due to a latching process. This design contributes to the drive being protected from such impact forces and thus damage. In order to suitably distribute loads for the purpose of damage prevention, the bracing lever in particular braces the pivotable end of the swing arm. 
     In one design of the invention, pivoting movements of the bracing lever are effected by a bolt, preferably by the stated second bolt, of the rotary disk. The bracing lever can thus be moved out of its bracing position at a suitable time in order to make the gap smaller by subsequent pivoting of the swing arm. The bracing lever is preferably pre-tensioned by a spring and namely in such a way that the bracing lever can be pivoted into its bracing position by spring force. 
     In one design of the invention the catch and pawl are arranged close to the axis around which the swing arm can be pivoted. The distance of the axes of the catch and pawl to the axis of the swing arm is therefore less than the distance between the axes of the catch and pawl to the end of the swing arm which is pivoted. A beneficial lever ratio is thus provided in order to be able to move the locking mechanism for example against sealing pressure with great force. 
     In one design of the invention, the catch can be pivoted away from the opening position when it is latched. If there are several ratchet positions, i.e. a main ratchet and a pre-ratchet, this applies to the main ratchet position. In particular, there is no stop which is capable of limiting this pivoting away from the (main) ratchet position if the locking bolt is moved beyond the envisaged latching position, i.e. opposite to the opening movement or in the direction of the overstroke position of the catch. Thus, risks of injury are prevented. If a person falls onto the systematically closed motor hood, the motor hood is also advantageously soft in the area of the latch in this execution form. 
     The latching device preferably possesses one or several microswitches with which positions of one or several components of the latching device can be ascertained. This is used in particular to suitably control the drive. 
    
    
     
       The following are shown: 
         FIG. 1 : Latch in open position; 
         FIG. 2 : First phase during a latching process; 
         FIG. 3 : Second phase during a closure process; 
         FIG. 4 : Third phase during a closure process; 
         FIG. 5 : Latch in ratcheted position; 
         FIG. 6 : Latch with catch in an overstroke position. 
     
    
    
       FIG. 1  shows a catch  1  with a collecting arm  2  and a load arm  3  in its open position. The catch  1  is pivotably attached with an axis  4  on a swing arm  5 . The swing arm  5  can be rotated around its axis  6 . The axis  6  is attached to a non-illustrated chassis directly or, for example, indirectly to the chassis of a motor vehicle via a non-illustrated latch plate. The catch can be latched by means of a pawl  7 . The pawl  7  is pivotably attached to the swing arm  5  by means of an axis  8 . The pawl  7  possesses a ratchet surface  9 . This ratchet surface  9  is adjacent to the ratchet surface  10  of the catch  1  when the catch  1  is latched. 
     A retaining lever  11  is pivotably attached to the swing arm  5  with an axis  12  in a middle area of the swing arm  5 . The retaining lever  11  acts as an impact absorber in order to protect the subsequently described drive unit from damage when the hood is closed. 
     The swing arm  5  is equipped with a protruding stop  13  which limits the pivoting of the retaining lever  11  in an anti-clockwise direction. The retaining lever  11  is preferably pre-tensioned by a non-illustrated spring so that this can be pivoted by pre-tensioning in the direction of the stop  13 . A control contour  14  is attached to the latch plate or directly to the chassis. This controls the pivoting of the retaining lever  11 . 
     In the shown open position of the locking mechanism, the pivotable, arch-shaped end  15  of the swing arm  5  is braced on a pivotable end  16  of a bracing lever  17 . The bracing lever  17  is attached to a latch plate or directly to the chassis with an axis  18 . The bracing lever  17  can be pivoted around the axis  18 . 
     A drive disk  19  is pivotably located around its axis  20 . The axis  20  is attached to a latch plate or directly to the chassis. A first bolt  21 , a second bolt  22  and a third bolt  23  protrude from the drive disk  19 . The three bolts  21 ,  22  and  23  and the axis  20  are preferably arranged roughly along a straight line in order to be able to utilize the rotary movements of the drive disk particularly well and simultaneously keeping the construction space small. The first bolt  21  is arranged on the edge of the drive disk  19 . The second bolt  22  is located between the axis  20  and the first bolt  21  near to the first bolt  21 . The third bolt  23  is arranged near to the axis  20 . The axis  20  is located between the second bolt  22  and the third bolt  23 . The drive disk  19  can be rotated around its axis  20  by a non-illustrated electrical drive. 
     There is a pivotable lever  24  with a T-shaped end which can be rotated around its axis  25 . The axis  25  is attached to a latch plate or directly to the chassis. There are preferably also two stops  26  and  27  for the lever  24  with the T-shaped end which are attached to a latch plate or directly to the chassis. The stops  26  and  27  limit the pivoting movement of the lever with the T-shaped end  24 . 
     The pivotable lever with the T-shaped end  24  limits rotary movements of the disk  19 . Thus, in the illustrated open position the first bolt  21  of the drive disc  19  is adjacent to the T-shaped end of the lever  24 . Consequently, the drive disc  19  can no longer be rotated in an anti-clockwise direction. In this position, the T-shaped end of the lever  24  preferably lies adjacent to the bolt-shaped stop  27  which ensures that the drive disk  19  can no longer be rotated in an anti-clockwise direction. Consequently, a mechanical end stop is attained. 
     There is a rod  28  with which the pawl  7  can be pivoted. The rod  28  is only sketched and suitably connected to the pawl  7  on the one hand and a drive on the other hand, for example, to the drive which is also capable of rotating the drive disk  19 . The rod  28  can be pivotably connected with the pawl  7  with one end  29 . Alternatively or additionally, the end  29  can be adjacent to a protrusion  30  of the pawl  7  in order to pivot the pawl  7  for example against a spring force out of a ratchet position. The pawl  7  can therefore be pre-tensioned in one execution form by a non-illustrated spring in such a way that this spring is capable of moving the pawl  7  into its ratchet position. 
     A brake element, damping element or stop  31  can be attached to the swing arm  5  which is capable of limiting or braking a pivoting of the catch  1  in a clockwise direction, at least temporarily. 
     There are microswitches  32 ,  33  and  34 , with which positions of locking mechanism components can be detected. The position of the catch  1  is detected with a first microswitch  32  for example. The position of the drive disk  19  is detected with a second microswitch  33  for example. The position of the swing arm  5  is detected with a third microswitch  34 , for example. However, other alternative or additional microswitches can be provided for which detect other positions and/or other components. 
     Furthermore, in  FIG. 1 , a locking bolt  35  is shown during latching of a pertaining hood which is attached to a non-illustrated hood of a motor vehicle. The locking bolt  35  has not yet reached the collecting arm  2  of the catch  1 . The hood is still open. 
     The axes  4  and  8  of the catch  1  and pawl  7  are relatively near to the axis  6 , the bearing point of the swing arm and thus relatively far from the end  15  of the swing arm  5  in order to thus provide a beneficial lever ratio. 
     If, starting from  FIG. 1 , the hood of the motor vehicle is further closed, the locking bolt  35  initially reaches the collecting arm  2  of the catch  1  and subsequently rotates the catch  1  in a clockwise direction until the load arm  3  of the catch  1  strikes the retaining lever  11 . The thus associated impact is initiated via the retaining lever  11  into the swing arm  5 . From here, the impact or the associated forces are conducted into the chassis on the one hand via the axis  6  of the swing arm  5  and on the other hand via the bracing lever  17 . The drive disc  19  is thus protected from impact forces occurring during latching. Additionally, the collecting arm  2  can have attained the dampening element  31  in order to additionally conduct impact forces from the catch  1  into the swing arm  5 . The catch  1  has attained a position which would enable the pawl  7  to be moved into its ratchet position. However, this is initially prevented by the rod  28 . The hood gap is for example more than 10 mm, in particular 15 mm between the hood and headlight grille or radiator grille. 
     If the catch  1  reaches the position shown in  FIG. 2 , the microswitch  32  is thus activated, for example. Thus, the drive which is capable of driving or rotating the drive disk  19  can be set in motion. Whereupon the drive disk  19  rotates in a clockwise direction. The second bolt  22  thus reaches the bracing lever  17  and for example captures a protrusion of the bracing lever  17 . Further rotation of the drive disc  19  in a clockwise direction therefore leads to the bracing lever  17  being pivoted out of its position shown in  FIG. 2  in a clockwise direction. The underside of the arch-shaped end  15  of the swing arm  5  is supported meanwhile by the second bolt  22 . A further rotation of the drive disk  19  in a clockwise direction results in the swing arm  5  being pivoted around its axis  6  in a clockwise direction and ultimately reaching the position shown in  FIG. 3 . This can be achieved by the latching movement of the door or flap or alternatively or additionally by gravity which impacts accordingly on a hood. A door or hood gap is decreased accordingly. The gap dimension is thus reduced to less than 10 mm, thus for example to 7 mm. 
       FIG. 3  clarifies that the lever with the T-shaped end meanwhile has loosened from the stop  27 . This lever has, for example, been pivoted into the position shown in  FIG. 3  due to gravity. It is significant that the catch  1  has still not been latched although the hood gap is still only a few millimeters, thus, for example, a maximum of 7 mm, preferably a maximum of 5 mm. This is for safety reasons as, for example, a finger cannot be trapped in the hood gap. Only when the hood gap is sufficiently small that fingers can no longer fit into the gap a further rotation of the drive disk  19  leads to the rod  28  being moved into a position which causes the pawl  7  to latch the catch  1 . However, it can also be activated with attainment of the position shown in  FIG. 3 , for example the microswitch  33 . Thus, a separate drive can be set in motion for the rod  28  which causes the pawl  7  to latch the catch  1  by relevant movement of the rod  28  as shown in  FIG. 4 . 
     As illustrated in  FIGS. 3 and 4 , the third bolt  23  of the drive disk  19  engages into the arch-shaped end  15  of the swing arm  5 . The gap dimension is still several mm and is, for example, between 5 and 7 mm. A further rotation of the drive disk  19  in a clockwise direction results in the position shown in  FIG. 5  ultimately being attained by closure. The third bolt  23  of the drive disk  19  which is meanwhile located within the arch-shaped end  15  of the swing arm  5  has pivoted the swing arm  5  around its axis  6  further in a clockwise direction. This can take place against a counterpressure, such as the sealing pressure of a seal for the hood. Thus, the hood gap is further reduced without fearing the risk of injury. The gap dimension can thus have been reduced to less than 1 mm, thus for example to not more than 0.2 mm or not more than 0.1 mm. 
     Due to the control contour  14  the retaining lever  11  is pivoted out of its position retaining the catch  1  in a clockwise direction around its axis  12 . The first bolt  21  of the drive disk  19  has struck the other side of the T-shaped end of the lever  24  of the relevantly pivotable lever and pivoted this lever around its axis  25  in an anti-clockwise direction. This pivoting movement is finally limited by attainment of the stop  26  as shown in  FIG. 5 . A further rotation of the drive disk  19  in a clockwise direction is then no longer possible. By provision of the pivoting lever with the T-shaped end  24  rotation of the drive disk  19  is limited on the one hand. On the other hand, especially large rotational angles of the drive disk are facilitated and in particular also rotational angles of more than 360°. 
     As the retaining lever  11  according to  FIG. 5  is pivoted out of its retaining position, it is possible that the catch  1  is pivoted further in a clockwise direction, as shown in  FIG. 6 . This protects people who fall onto the pertaining hood, for example. The hood can thus be pushed further downwards in the area of the latch, without such a movement being blocked by the locking mechanism which reduces the risk of personal injury. So-called pedestrian protection can thus be achieved. The locking bolt  35  can in particular be moved by more than 10 mm, preferably by at least 20 mm further in the opposite direction to the opening direction. The latched catch can be pivoted away for this purpose by at least 10°, preferably by at least 20° from the opening position, as shown in  FIG. 6 . 
     The element  31  can be a plastic element with a predetermined breaking point. When, for example, snow is on the hood and the electrical drive lifts the hood, the plastic element prevents the catch from skidding downwards. The element  31  prevents undesirable skidding. The predetermined breaking point can break if a pedestrian falls onto the hood. 
     Alternatively, i.e. where the plastic element is not present a strong spring can be arranged on the catch which in turn is strong enough to lift the hood with a snow load. 
     An opening of the locking mechanism takes place vice versa accordingly. 
     REFERENCE SIGN LIST 
     
         
         
           
               1 : Catch 
               2 : Collecting arm 
               3 : Load arm 
               4 : Catch axis 
               5 : Swing arm 
               6 : Swing arm axis 
               7 : Pawl 
               8 : Pawl axis 
               9 : Pawl ratchet surface 
               10 : Catch ratchet surface 
               11 : Retaining lever 
               12 : Retaining lever axis 
               13 : Stop or rotation limiting element for retaining lever 
               14 : Control contour for retaining lever 
               15 : Arch-shaped end of the swing arm 
               16 : Pivotable end of a bracing lever 
               17 : Bracing lever 
               18 : Bracing lever axis 
               19 : Drive disk 
               20 : Drive disk axis 
               21 : First bolt of the drive disk 
               22 : Second bolt of the drive disk 
               23 : Third bolt of the drive disk 
               24 : Lever with T-shaped lever end 
               25 : Axis for lever with the T-shaped end 
               26 : Stop or rotation limiting element for the lever with the T-shaped end 
               27 : Stop or rotation limiting element for the lever with the T-shaped end 
               28 : Rod for pivoting of the pawl 
               29 : Rod end on the pawl 
               30 : Pawl protrusion 
               31 : Brake element, damping element or stop for catch preferably with pre-determined breaking point 
               32 : Microswitch 
               33 : Microswitch 
               34 : Microswitch 
               35 : Locking bolt 
               36 : Protrusion of the bracing lever