Motor vehicle door latch with primary and secondary pawl

The invention relates to a latch for a door or flap of a motor vehicle with a locking mechanism comprising a catch (3), a primary pawl (1) for ratcheting with the catch (3) in a main ratchet position and a separate secondary pawl (2) for ratcheting with the catch (3) in a pre-ratchet position, whereby only in the case of overload can the secondary pawl (2) additionally ratchet to the primary pawl (1) with the catch (3) in the main ratchet position. The invention furthermore relates to a latch for a door or a flap of a motor vehicle with a locking mechanism comprising a catch (3) with a load arm (7) and a catching arm (8) a primary pawl (1) to ratchet with the load arm (7) of the catch (3) in a main ratchet position and a separate secondary pawl (2) to ratchet with the catching arm (8) of the catch (3) in a pre-ratchet position, whereby the catch (3), the primary pawl (1) and the secondary pawl (2) are arranged on the same plane. A reduction of the complexity, e.g. an automatic closure aid and increased stability, i.e. the tensile strength are enabled simultaneously.

The invention relates to a latch for a door or flap of a motor vehicle with a locking mechanism comprising a catch, a primary pawl for ratcheting with the catch in a main ratchet position and a separate secondary pawl for ratcheting with the catch in a pre-ratchet position.

BACKGROUND

For motor vehicle latches, high stability is demanded so that even when great forces act on the door or flap, for example by misuse or in the event of a crash, no unscheduled opening occurs.

With increasing automation in the automotive field for provision of greater operating convenience, motorized closure aids are increasingly used for bringing a door or flap into the scheduled closed position by means of motor power.

However, such closure aids are of a comparatively complex construction in order to execute the necessary pulling distance into the closed position, i.e. into the main ratchet position of the catch. The complex construction increases the construction weight which must be saved elsewhere without reducing the stability mentioned at the start.

Publications DE102007003948A1, DE2839070A1 and DE19902561A1 reveal latches for a door or a flap of a motor vehicle with a locking mechanism comprising a catch and at least a pawl.

SUMMARY

Unless specified otherwise hereafter, the aforementioned characteristics of a locking mechanism can be part of the invention individually or in combination.

In view of what has been explained above, it is the task of the invention to provide a further developed latch of the type stated at the beginning.

The task of the invention is solved by a latch with the characteristics of claim1and the sub-claim. Advantageous designs arise from the sub claims.

A latch for a door or flap of a motor vehicle with a locking mechanism comprising a catch, a primary pawl for ratcheting with the catch in a main ratchet position and a separate secondary pawl for ratcheting with the catch in a pre-ratchet position solves the task, whereby only in the case of overload the secondary pawl in addition to the primary pawl can ratchet with the catch in the main ratchet position.

The door is generally a side door. The flap is usually the trunk or the tailgate. However, the flap can also be the motor hood.

Locking mechanism means a usual locking mechanism of a latch for a door or a flap of a motor vehicle, the preferred construction and functionality of which is explained in detail further below.

A primary and separate secondary pawl are two separate components. Two separate components can normally be moved independently of one another. Compared to a normal load, overload means an increased load. Load means a force which acts on a catch in the main ratchet position in the opening direction. In particular, the load or force is transferred from a locking bolt incorporated to the catch and can arise, for example, by a pulling of the door or flap.

Overload predominates especially if a gap is closed between the secondary pawl and the catch by the overload, whereby the same gap is distanced in operation for a normal load and the secondary pawl is distanced from the catch—in particular from the collecting arm of the catch.

In the case of a closed gap, the secondary pawl touches the catch directly. Consequently, the catch can brace against the overload or force of the overload on the secondary pawl.

In other words, an overload predominates especially if an elastic deformation of the catch and/or the primary pawl leads to closure of the gap between the secondary pawl and the catch, whereby the same gap in operation with a normal load maintains the secondary pawl at a distance from the catch.

By means of a latch for a door or flap of a motor vehicle with a locking mechanism comprising a catch, a primary pawl for ratcheting with the catch in a main ratchet position and a separate secondary pawl for ratcheting with the catch in a pre-ratchet position, whereby only in the case of overload does the secondary pawl, in addition to the primary pawl, ratchet with the catch in the main ratchet position, enabling both a reduction of the complexity of an automatic closure aid and increased stability, for example of the tensile strength.

The reduction of the complexity is specifically caused by the fact that the provision of the separate secondary pawl means that the rotary path of the catch from the pre-ratchet position into the main ratchet position can be reduced. If, for example, a closure aid should be implemented which in particular executes motorized rotation of the catch from the pre-ratchet position to the main ratchet position, a simple and compact mechanism with a comparatively light weight can already be sufficient. The increase of the construction weight of the latch by the implementation of a closure aid can thus be kept low.

At the same time, as a result of the increased stability weight can be saved on the catch and the pawl to fulfill safety requirements nevertheless. Because due to the additional ratcheting of the secondary pawl with the catch in the main ratchet position during overload, the load is distributed on the primary and secondary pawl and relieves the primary pawl in particular.

A locking mechanism generally encompasses a catch to incorporate a locking bolt and a pawl to hold the catch with the incorporated locking bolt in the closed state of the locking mechanism. In principle, a locking mechanism is set up in such a way that, due to scheduled activation of the locking mechanism by the user, the pawl is disengaged from the catch. Consequently, the catch can release the locking bolt again.

The motor vehicle latch preferably encompasses a latch plate made of metal or a metallic latch case with the latch plate, whereby the locking mechanism is accommodated with the catch and the pawl on the latch plate or in the latch case. The latch plate usually demonstrates an inlet slot which allows the locking bolt to reach the latch in order to be incorporated by the rotatable catch of the locking mechanism and to be held by ratcheting of the pawl with the catch. Either the locking bolt is attached to the vehicle chassis and the latch plate or latch case is attached to the door or flap or vice versa.

The catch of a motor vehicle latch normally has a load arm and a collecting arm which jointly form a fork-shaped inlet slot of the catch into which the locking bolt goes especially when passing the inlet slot of the latch plate when the door or flap is closed. The locking bolt then rotates the catch from an open position in the direction of the closed position. If the catch has reached the closed position, it is ratcheted in this position via the pawl. The locking bolt can then no longer leave the inlet slot of the catch. This ratchet position is called a main ratchet position.

In particular, the locking mechanism demonstrates a second ratcheting position, namely the so-called pre-ratchet position. The pre-ratchet position serves to retain the door or flap for safety reasons if this does not reach the main ratchet position during closure. In the pre-ratchet position the catch is consequently not completely closed. However, an opening movement of the catch by the pawl is already prevented. In the main ratchet position, the catch and thus the locking mechanism is completely closed. The pre-ratchet thus constitutes a transitional state between the open position and the closed position or main ratchet position.

Ratcheting of the catch by the pawl in the main ratchet position or the pre-ratchet position generally occurs via corresponding main ratchet surfaces or pre-ratchet surfaces which are adjacent to one another in the main ratchet position or pre-ratchet position in order to retain the catch in the main ratchet position or the pre-ratchet position.

In particular, the locking mechanism has a blocking lever in addition to the pawl to retain the pawl in the main ratchet position in order to generally reduce the background noise when the motor vehicle door is closed and to reduce the necessary activation force for triggering, i.e. disengaging or opening, the locking mechanism. For a locking mechanism thus created, the relative position between the catch and the pawl is in principle formed in such a way that a force acting from the catch onto the pawl in the opening direction induces an opening torque into the pawl favoring the release or disengagement of the catch instead of fastening of the catch.

The blocking lever thus serves to fasten the pawl in the position ratcheted with the catch. For example, the force in the opening direction which acts from the catch onto the pawl is generated by compression of a rubber seal of the door or flap. An opening moment constantly acts on the pawl in this case in the closed position. To trigger the locking mechanism, a disengagement of the fastening between the blocking lever and the pawl is then sufficient so that the pawl releases the catch and the locking mechanism can open. Opening of the latch is thus possible with especially little expenditure of force.

In one design form, in the case of normal loads a gap distances the secondary pawl from the catch in an opening direction of the catch, when the catch is in the main ratchet position. The secondary pawl is therefore arranged in the main ratchet position of the catch in the opening direction of the catch and separated from the catch by the gap.

The opening direction is the direction in which the catch rotates in order to get from the main ratchet position in the closed position of the locking mechanism into the opening position. Normal load is a load smaller than the overload.

A ratcheting of the secondary pawl with the catch in the main ratchet position is enabled in addition to the primary pawl by means of the gap in the case of overload. Consequently, in the case of overload a load division can occur between the primary and secondary pawl and in the case of normal loads in contrast an especially simple triggering of the locking mechanism. Additionally, an overdefinition of ratchet connections and thus an especially reproducible and reliable ratcheting is enabled in the main ratchet position for normal loads.

In one design form, in the case of overload a deformation of the catch and/or primary pawl leads to closure of the gap. Closure of the gap means that the secondary pawl comes into direct contact with the catch, i.e. in contact with the catch. Consequently, the catch can be braced on the secondary pawl against the overload or force of the overload. A self-controlling mechanism can thus be facilitated to distribute the load in the case of an overload.

In one design form, the deformation of the catch and/or the primary pawl is an elastic deformation. After the occurrence of an overload, the locking mechanism thus requires no repair or maintenance measure to continue to function properly. When overloaded, the catch and/or primary pawl are therefore so greatly deformed that the catch is pressed against the secondary pawl when the gap is closed and can thus be braced on the secondary pawl. With normal loads, the catch and/or the primary pawl are not deformed or only slightly deformed. Consequently, the catch is pressed in the direction of the secondary pawl. However, the gap between the catch and secondary pawl remains open.

In the case of scheduled opening of the locking mechanism, the gap distances the secondary pawl from the catch in the main ratchet position especially such that no frictional force occurs between the secondary pawl and the catch to trigger the locking mechanism from the main ratchet position or needs to be overcome to open the locking mechanism.

In one design form, an opening moment is induced into the primary pawl and/or the locking mechanism demonstrates a blocking lever to block the primary pawl in the ratcheted state with the catch in the main ratchet position in the case of a load acting on the catch in an opening direction. By means of the primary pawl with an opening moment and/or the provision of a blocking lever as described above, an especially great convenience can be provided to the user.

In one design form, the catch, the primary pawl and the secondary pawl are arranged on the same plane. Arranged on the same plane means that the catch, the primary pawl and the secondary pawl are pivotably accommodated on a common rotational plane, i.e. are therefore not arranged in different rotational planes. In other words, the catch, the primary pawl and the secondary pawl all mutually overlap if viewed transverse to the catch rotational axis. In particular, the catch rotational axis, the primary pawl pivoting axis and the secondary pawl pivoting axis are all arranged in parallel to one another. An especially compact design with an especially light weight can thus be enabled.

In one design form, the blocking lever is arranged on the same plane as the catch, the primary pawl and the secondary pawl. An especially compact design with an especially light weight can thus be enabled.

In one design form, a triggering lever of the locking mechanism acts simultaneously on the blocking lever and the secondary pawl in order to be able to disengage the locking mechanism both from the pre-ratchet position and the main ratchet position to open the latch by the same triggering lever. If the triggering lever is activated to open the latch, both blocking of the primary pawl by the blocking lever in the main ratchet position of the catch and also ratcheting of the catch in the pre-ratchet position by the secondary pawl can thus be disengaged. An additional triggering lever and thus additional weight can be saved and the mechanics can be executed with particular ease.

In one design form, the blocking lever is provided by a blocking lever section of the secondary pawl, the blocking lever and the secondary pawl are one and the same component and/or the blocking lever and the secondary pawl are formed as a single part or component. Thus, there is no need to provide an additional lever for this functionality needs and the number of components and weight can accordingly be reduced. The blocking lever section assists the stability of the secondary pawl, so to speak, due to its volume.

In one design form, the catch and the secondary pawl are formed and arranged in such a way that when the catch rotates from an open position in the direction of the main ratchet position, the secondary pawl is pivoted after passing the pre-ratchet position by the catch in such a way—especially away from the catch—that the blocking lever section—in particular due to a free-lifting recess—enables blockade-free pivoting out of the primary pawl to ratchet with the catch in the main ratchet position.

Pivoting out to ratchet with the catch means a snapping movement as for a drop-latch, i.e. the primary pawl is initially pivoted outwards as a result of displacement by the external contour of the catch in order to pivot back in the direction of the catch again after overcoming a radial protrusion of the catch in order to ratchet on the other side with the protrusion. Consequently, the catch can no longer rotate into the opposite direction, i.e. no longer in the opening direction. Reliable ratcheting, saving of additional levers and additional weight, can thus be guaranteed.

In a further design form, the primary pawl locks the secondary pawl in the blockade-free pivoted out position—preferably by adjacency or gliding on the free lift recess of the blockade lever section—such that the blockade lever section is prevented during the blockade-free pivoting out of the primary pawl from pivoting (back) into the blockade position to block the primary pawl. Reliable ratcheting, saving additional levers and additional weight, can thus be guaranteed.

In one design form, only the secondary pawl can ratchet the catch in the pre-ratchet position. An especially short rotational path of the catch from the pre-ratchet position into the main ratchet position can thus be achieved.

In one design form, the locking mechanism is set up in such a way that the primary pawl and the secondary pawl can respectively only ratchet with the same arm of the catch, i.e. either the load arm or the collecting arm. The secondary pawl can therefore only ratchet with the collecting arm, for example, in the pre-ratchet position and in the main ratchet position. Ratcheting of the secondary pawl with the load arm is not possible according to this design form. This applies analogously to the primary pawl, whereby the primary pawl can preferably only ratchet with the catch in the main ratchet position.

An especially short rotational path of the catch from the pre-ratchet position into the main ratchet position can thus be provided in particular with an arrangement of the catch, the primary pawl and the secondary pawl in the same plane.

In one design form, the locking mechanism is set up in such a way that the primary pawl and the secondary pawl can only ratchet with different arms of the catch, i.e. either the load arm or the collecting arm. The primary pawl and the secondary pawl can therefore not both ratchet with the load arm, especially not in the pre-ratchet position and also not in the main ratchet position of the catch. For example, regardless of the pre-ratchet or main ratchet, the secondary pawl can only ratchet with the collecting arm, for example and the primary pawl can only ratchet with the load arm, whereby the primary pawl can preferably only ratchet with the catch in the main ratchet position.

An especially short rotational path of the catch from the pre-ratchet position into the main ratchet position can thus be executed in particular with an arrangement of the catch, the primary pawl and the secondary pawl in the same plane.

In one design form, the locking mechanism is set up in such a way that the primary pawl can ratchet with the load arm and the secondary pawl can ratchet with the collecting arm. An especially short rotational path of the catch from the pre-ratchet position into the main ratchet position can thus be executed in particular with an arrangement of the catch, the primary pawl and the secondary pawl in the same plane in this design form too.

A further aspect of the invention to solve the task stated at the beginning relates to a latch for a door or a flap of a motor vehicle with a locking mechanism comprising a catch with a load arm and a collecting arm, a primary pawl to ratchet with the load arm of the catch in a main ratchet position and a separate secondary pawl to ratchet with the collecting arm of the catch in a pre-ratchet position, whereby the catch, the primary pawl and the secondary pawl are arranged on the same plane. Due to the further aspect of the invention, a reduction of the complexity of an automatic closure aid and increased stability, i.e. of the tensile strength, are simultaneously enabled.

The explanations and design forms of the solution of the task described at the start also apply identically to the further aspect of the invention.

Design examples of the invention are explained in further detail hereafter on the basis of figures. Characteristics of the design examples can be combined individually or plurally with the claimed objects.

DETAILED DESCRIPTION

FIG. 1shows a locking mechanism in a closed position. The primary pawl1is ratcheted with the catch3in the main ratchet position and is blocked by the blockade lever section5of the secondary pawl2in this ratcheted position or this ratcheted state. The normal load is depicted by a horizontal arrow in the opening direction. A gap4distances the secondary pawl2from the catch3in the opening direction of the catch3. The catch3, the primary pawl1and the secondary pawl2and the blockade lever section5are arranged on the same plane. The primary pawl is illustrated with the load arm7of the catch3ratcheted in the main ratchet position.

The pre-ratchet position of the catch3is depicted in dashes, whereby the secondary pawl2is illustrated with the collecting arm8of the catch3ratcheted in the pre-ratchet position. The position of the secondary pawl2in the ratcheted state with the catch3in the pre-ratchet position precisely or roughly preferably corresponds to the position in which the blockade lever section5blocks the primary pawl1in the ratcheted state with the catch3in the main ratchet position, in order to facilitate mechanics of an especially simple construction. This blockade position can also be provided slightly displaced in a rotated manner, especially in a clockwise direction in order to guarantee reliable ratcheting in the case of overload. If the catch3is in the pre-ratchet position, the primary pawl1can preferably be adjacent on the load arm7on the side of the inlet slot9of the catch3, i.e. not as illustrated inFIG. 1.

The difference of the rotational positions of the catch3in the pre-ratchet position and the main ratchet position results in the rotational path. Compared to a locking mechanism with only one pawl, which is consequently provided for ratcheting with the catch in the pre-ratchet position and in the main ratchet position, an especially small rotational path is enabled.

FIG. 2shows the locking mechanism ofFIG. 1in the case of an overload which is transferred from the locking bolt11onto the catch3. The primary pawl1and/or the catch3deform under the overload. Consequently, the gap4closes and the secondary pawl also ratchets with the catch3, namely with the collecting arm8. The load is thus distributed onto the primary pawl1and the secondary pawl2.

A closure process and opening process can occur as described hereafter. The locking bolt11encounters the collecting arm8of the catch3in the opening position and rotates the catch against a non-illustrated catch spring in the direction of the closed position, i.e. the main ratchet position. In particular, the primary pawl1and/or the secondary pawl2demonstrate non-illustrated torsion springs with a spring pre-tensioning into the opposite torsional direction as the catch spring. The primary pawl1is thus displaced outwards or pivoted outwards by the side of the collecting arm8deflected from the inlet slot9of the catch3. However, the ratchet surface of the primary pawl1on the free end of the primary pawl1is formed in such a way that ratcheting with a ratchet surface of the collecting arm8is not possible on the free end of the collecting arm8.

In one design form, the maximum radius of the collecting arm8is smaller than the maximum radius of the load arm7. The primary pawl can thus pass the collecting arm8, even if the blockade lever section5is located in the blockade position or at least in a blocking position for the primary pawl1in the ratcheted state with the catch3in the main ratchet position.

After the collecting arm8has passed the primary pawl1, the collecting arm8displaces the secondary pawl2outwards or deflects the secondary pawl2. In particular, the ratchet surface or pre-ratchet ratchet contour12of the collecting arm8viewed in the direction of the catch rotational axis14has in particular the shape of a recess, in particular a V-shaped recess centrally on the free end of the collecting arm8. A corresponding pre-ratchet contour13of the secondary pawl2engages into this pre-ratchet contour12and thus retains the catch3in the pre-ratchet position if the load exerted on the catch3decreases after passing the pre-ratchet position and before reaching the main ratchet position and the catch3would otherwise rotate beyond the pre-ratchet position back in the opening direction. With an ongoing load, however, the pre-ratchet contour12of the collecting arm8also displaces the pre-ratchet contour13of the secondary pawl2. Consequently, the secondary pawl2pivots out and the catch3is passed in the direction of the closed position.

After the catch3has passed the pre-ratchet position during rotation in the direction of the main ratchet position, the circumferential contour displaces the catch3the secondary pawl2in particular in such a way outwards that the blockade lever section5of the secondary pawl2preferably enables the primary pawl1blockade-free pivoting out by means of a free-lifting recess15, when the primary pawl1encounters the load arm7and for ratcheting—or better snapping in—is displaced outwards and pivoted out in order to engage into the envisaged ratchet position with the catch3in the main ratchet position after overcoming the circumferential area with the maximum radius of the load arm. The main ratchet contour16of the primary pawl1is then adjacent on the main ratchet contour17of the load arm7.

The gap4extends from the overload main ratchet contour20of the catch3to the overload main ratchet contour19of the secondary pawl2. In the case of overload, the gap4is closed and the overload main ratchet contour19of the secondary pawl2engages into the overload main ratchet contour20of the catch3or ratchets with it.

With the pivoting out of the primary pawl1for the snapping movement the free end of the primary pawl1, especially an area of the main ratchet contour16of the primary pawl1, goes into the free-lifting recess of the blockade lever section5in such a way that the blockade lever section5and thus the secondary pawl2are prevented during blockade-free pivoting out of the primary pawl1from pivoting back into the blockade position to block the primary pawl. Only after engagement of the primary pawl1into the catch3in the main ratchet position does this prevention cease to apply. Consequently, with the engagement of the primary pawl1immediately the second pawl2and thus the blockade lever section5into the blockade position for blocking of the primary pawl1in the ratcheted state pivots with the catch3in the main ratchet position. In particular, blocking takes place externally crucially radially in the direction of the catch rotational axis14.

For opening of the locking mechanism from the pre-ratchet or the main ratchet, only activation of the triggering lever6is necessary, preferably against the spring pre-tensioning of the secondary pawl2.

If the triggering lever6is activated to detach the pre-ratchet, the secondary pawl2and thus the pre-ratchet contour13is pivoted away from the pre-ratchet contour12of the catching arm8. Consequently, the catch3can pivot in the opening direction.

If the triggering lever6is activated to detach the main ratchet, the secondary pawl2and thus the blockade lever section5is pivoted out of the blockade position. Consequently, the primary pawl1can pivot out by means of the opening moment into the area of the free-lift recess15. Consequently, the catch3can pivot in the opening direction. For normal loads, the gap4ensures that only the frictional force between the blockade lever section5and the primary pawl1needs to be overcome to trigger the locking mechanism with regard to the ratchet connections. The locking bolt11can thus leave the latch by means of the inlet slot10in the latch case18.

In particular, the primary pawl1is formed lengthwise or crucially L-shaped and/or accommodated pivotably to the end opposite the main ratchet contour16. In particular, the secondary pawl is L-shaped, whereby the in particular lengthwise and/or radial-leg of the L-shape preferably demonstrates the pre-ratchet contour13and/or the overload main ratchet contour19on the free radial end. In particular, the other crucially bent or tangentially formed L-leg of the L-shape in the circumferential direction is the blockade lever section5. The radius of the external contour of the blockade lever section5is preferably between 20% and 70% of the radius of the free end of the radially extending L-leg of the L-shape.

The catch3is preferably arranged on the opposite side from the inlet slot10of the latch case18, like the primary pawl1and the secondary pawl2.