Lock

Abstract

Lock (10), in particular for a backrest of a motor vehicle, comprising a housing (12), a rotary latch (20) rotatably mounted in the housing (12), a pawl (18) for the rotary latch (20) and an immobilization element (16) for locking the pawl (18) in an unlocked position and immobilizing a locking bracket received in the rotary latch in a closed state of the lock, characterized in that the immobilization element (16) is driven by the rotary latch (20) and is guided by a guide topology (66) exclusively in a predetermined direction of movement (72) along a circular path (14).

Description

The present invention relates to a lock, in particular for a backrest of a motor vehicle.A lock of the type mentioned at the beginning is used, for example, in a passenger car in order to lock a convertible backrest of a rear bench in an upright position. In this case, a striker is generally provided on the vehicle body side, which engages in a rotary latch of the lock provided on the backrest. For immobilizing the backrest in the erected position, an immobilizing element is provided which, in the closed state of the lock, acts on the striker accommodated in the rotary latch against the rotary latch in order to prevent a relative movement between the striker and the rotary latch, which could be perceived as unpleasant rattling noise by a vehicle occupant.To lock the rotary latch in the closed state, a pawl is provided, which is released from the rotary latch for opening the lock. During the release of the pawl, the pawl brings the immobilizing element against the restoring force of a restoring element into a position in which the immobilizing element enables a sufficient overstroke of the rotary latch during the closing of the lock.Locks of this type have the disadvantage that they require a relatively great exertion of force by the user for opening.DE 10 2012 102 724 A1 discloses a motor vehicle door latch having a rotary latch mounted rotatably in a housing and a pawl for the rotary latch. US 2013 / 0 129 413 A1 and JP 2010-106 549 A disclose further prior art.The object of the invention is to create a lock which can be opened with less force exertion.The object is achieved by a lock having the features of claim 1 and in particular by the fact that the immobilization element is driven by the rotary latch and guided by a guide topology exclusively in a predefined direction along a round section.The invention is based on the general idea of decoupling the movement of the immobilization element from the pawl and instead controlling it by the rotary latch and a guide topology. This has the advantage that the lock according to the invention can be opened with less force exertion. Because the immobilization element can move along the guide topology only in the predetermined direction and not approximately in the direction opposite to the predetermined direction, the round section forms a one-way road to a certain extent, thereby ensuring that the immobilization element on its path through the guide topology at least assumes a position in which an overstroke of the rotary latch required for the closing operation is possible. In addition, the configuration according to the invention is particularly cost-effective to produce and simple to install, since fewer parts are required in comparison with known solutions.Advantageous embodiments can be taken from the dependent claims, the description and the drawings.According to one embodiment, the immobilization element comprises an engagement feature, in particular a first pin, and the rotary latch comprises a driver for entrainment of the engagement feature. Thus, a movement of the immobilization element can be effected in a simple and reliable manner by a rotation of the rotary latch.The immobilization element is advantageously guided along the round section in that the guide topology is formed in the housing and accommodates a second pin provided on the immobilization element. Alternatively, the guiding topology can be formed on the immobilization element and can receive a second pin provided on the housing. Furthermore, it is basically conceivable to design the guiding topology for guiding the immobilization element on the rotary latch.For better guidance of the immobilization element, the guide topology can comprise an inner guide surface and an outer guide surface, which together form a guide channel for the second pin defining the round section.Advantageously, the round section describes at least approximately a triangle.The first pin and the second pin may extend from opposite sides of the immobilization element. This has the advantage that the structure of the lock is simplified, since the rotary latch and the housing can be connected to the immobilization element on different sides thereof.Furthermore, the guiding topology can comprise a blocking element, for example a ramp, which prevents the second pin from being able to move counter to the predefined direction of movement. Such a ramp can have an inclined surface which rises in the direction of movement and merges into an end surface which lies substantially perpendicular to the direction of movement of the immobilization element. If the second pin slides over the ramp in the predetermined direction of movement, the pin runs onto the inclined surface and falls down again on the end surface. In the opposite direction, in which the immobilization element is not intended to move, the second pin abuts against the end face of the ramp. This easily prevents a movement of the second pin and thus of the immobilization element overall counter to the predefined direction of movement.Preferably, the second pin of the immobilization element is spring-mounted and / or the ramp is flexible. This makes it possible for the immobilization element to move at least not substantially out of its movement plane during sliding over the ramp. Since the immobilization element moves only within the plane of movement, no additional installation space is required outside the plane of movement in order for the immobilization element to be able to slide over the ramp.A preferably elastically deformable partition wall can be formed on the rotary latch, which prevents direct contact between a striker engaging in the rotary latch and the immobilization element. As a result, the immobilization element is shielded so to speak from the striker with the advantage that as a result, movements of the striker, in particular vibrations of the striker, which could lead to an undesired movement of the immobilization element, are not transmitted directly to the immobilization element.The immobilizing member may include a locking surface engageable with the ratchet to hold the ratchet in the unlocked position. This has the advantage that a better force transmission is achieved between the immobilization element and the pawl.Furthermore, the guide topology can comprise a guide stop which is designed to limit the movement of the immobilization element, in particular if the second pin is located in a corner of the triangle, and / or to guide the movement of the immobilization element.A spring can be connected between the rotary latch and the immobilization element, which spring is tensioned by a rotation of the rotary latch into the closed position. Such a spring performs an advantageous dual function in that it ensures both opening or opening of the rotary latch and also moving the immobilization element back into a release position or starting position.The immobilization element preferably has a third pin which is guided in a guide of the housing. The aforementioned spring can be a leg spring, one leg of which is in engagement with the rotary latch and the second leg of which is in engagement with the immobilization element, in particular at the third pin.A particularly cost-effective embodiment of the invention that is simple to install provides that the immobilization element is formed in one piece.For better guidance of the immobilization element, it can have an arm which is guided by a boundary on the housing side.A further advantageous embodiment of the invention provides that a first channel section of the guide topology is configured to guide the second pin from a position 1 in which the immobilization element is not engaged with the pawl to a position 2 in which the immobilization element and the pawl are engaged and the pawl is held in the unlocked position when the rotary latch is opened; a second channel section of the guide topology is configured to guide the second pin from the position 2 to a position 3 in which the immobilization element and the pawl are disengaged again and the rotary latch is locked by the pawl when the rotary latch is closed; the second channel section of the guide topology is furthermore designed, after the catch is locked by the pawl at position 3, to guide the second pin from position 3 to a position 4 in which the immobilization element is released in order to be able to be moved back into position 1, in particular by a spring; and a third channel section of the guide topology is designed to guide the second pin back from position 4 into position 1, wherein the immobilization element is moved from position 4 into position 1, in particular by said spring.In this context, position 1 is also referred to as the home or release position of the immobilization element, in which the immobilization element is not engaged with the pawl, while position 2 is also referred to as the locking position, because the immobilization element is engaged with the pawl in position 2 and locks it. Between position 3 and position 4, an overstroke of the rotary latch takes place. In this context, the term "overstroke" means that the rotary latch rotates even slightly further after being closed and locked by the pawl at position 3 until the second pin has arrived at position 4. In each of the positions 1, 3 and 4, the immobilizing element and the pawl are disengaged, so that each of these positions forms a release position.Positions 1, 2 and 4 may represent vertices of a substantially triangular round-section.As already mentioned, the lock is designed such that the movement of the immobilizing element is not controlled by the pawl, but ultimately is effected or controlled by the opening and closing of the rotary latch. This has the advantage that the force for moving the immobilization element is ultimately applied by the movement of the backrest and not by the actuation of a release lever. In particular, by closing the rotary latch, a spring can be prestressed, with the aid of which the rotary latch is subsequently opened again and the immobilization element is carried along by the rotary latch from the position 1 into the position 2. In contrast to a system in which the immobilization element is controlled by the pawl, it is therefore not necessary to apply a force for moving the immobilization element on the release lever in addition to the force for moving the pawl, whereby the required release force of the lock is reduced.The invention will be described below with reference to the attached drawings, using a purely exemplary embodiment. The following are shown: FIG. 1 shows a schematic diagram of a lock according to the invention; FIG. 2 shows a schematic diagram of a rotary latch of the lock of FIG. 1 ; FIG. 3 shows a schematic diagram of a immobilization element of the lock of FIG. 1 ; FIG. 4A shows a part of a housing of the lock of FIG. 1 ; FIG. 4B shows the part of the housing of FIG. 4A with the immobilizing element of FIG. 3 and a driver of the rotary latch of FIG. 2 ; FIG. 5 shows a flow diagram of a movement of the immobilization element of FIG. 3 in a guiding topology of the housing of FIG. 4A ; FIG. 6A shows the lock of FIG. 1 in a closed position; FIG. 6B shows the lock of FIG. 1 in a fully opened state; and FIG. 6C shows the lock of FIG. 1 in an overstroke position.FIG. 1 shows a lock 10, which serves, for example, in a passenger car for locking a backrest of a rear bench in an upright position. The lock 10 comprises a housing 12, a rotary latch 20 rotatably mounted on the housing 12, a pawl 18 rotatably mounted on the housing 12 for the rotary latch 20 and a plate-shaped immobilization element 16 displaceable relative to the housing 12 along a round section 14.For mounting the rotary latch 20 on the housing 12, the rotary latch 20 has a bearing bore 26, in which a bearing bolt 28 of the housing 12 is accommodated (FIGS. 1 and 2 ). Furthermore, the rotary latch 20 comprises a recess 24 which is designed to receive a striker 22 in an open position of the rotary latch 20 (FIG. 6B ) and to retain it in a closed position of the rotary latch 20 (FIG. 6A ). The rotary latch 20 further comprises a driver 30, at one end of which a hook-shaped receptacle 32 (FIG. 2 ) is formed in order to receive a first pin 34 (FIG. 3 ) of the immobilization element 16 and to carry the immobilization element 16 along with it during a rotational movement of the rotary latch 20.In the closed position (FIG. 6A ), the immobilization element 16 is supported on the housing 12 and presses the striker 22 accommodated in the recess 24 against the rotary latch 20, whereby the latter is rotated against the pawl 18. In this way, in the closed state of the lock 10, a immobilization of the striker 22 and the rotary latch 20 and thus ultimately of the backrest as a whole is achieved.The rotary latch 20 further comprises a separating wall 36 which extends from an edge of the recess 24 transversely to a movement plane of the rotary latch 20, into the sheet plane in FIG. 2 and which is designed to be flexible such that it can be elastically deformed to a small extent. In the closed position (FIG. 6A ), the partition 36 is arranged between the immobilizing element 16 and the striker 22 accommodated in the recess 24, and prevents a transmission of vibrations of the striker 22 to the immobilizing element 16 by preventing a direct contact between the striker 22 and the immobilizing element 16.The immobilization element 16 is formed in one piece as shown in FIG. 3 and has three pins 34, 38, 46 protruding from the immobilization element 16 transversely to a movement plane of the immobilization element 16, i.e. extending transversely to the leaf plane in FIG. 3, wherein the first pin 34 is formed, as already described, to be carried along by the driver 30 of the rotary latch 20.A second pin 38 engages, as shown in FIG. 4B, in a guide channel 40 of the housing 12 defining the round section 14 and is guided therein. The second pin 38 is formed in an end region of a resilient tongue 42 of the immobilization element 16 in order that it can move over a ramp 44 (FIGS. 4A and 5 ) formed in the guide channel 40 without the immobilization element 16 having to move altogether out of a movement plane of the immobilization element 16 for this purpose. The plane of movement is defined by the displacement of the immobilization element 16 along the round section 14, which is indicated by arrows 72 in FIG. 4B.A third pin 46 is formed in an end region of a first arm 48 of the immobilization element 16 extending in the movement plane and away from the pawl 18 and engages in a slotted guide 50 of the housing 12. Further, a leg spring 52 engages the third pin 46 to move the immobilization element 16 from an over-stroke position (FIG. 6C ) toward the closed position (FIG. 6A ). The immobilization element 16 is arranged at least partially between the rotary latch 20 and the housing 12 such that the first pin 34 protrudes from the one side of the immobilization element 16 namely in the direction of the rotary latch 20, while the second pin 38 and the third pin 46 protrude from the other side of the immobilization element 16, namely in the direction of the housing 12.The immobilization element 16 further comprises a second arm 54 pointing toward the pawl 18, which extends in the plane of movement of the immobilization element 16 and is guided in a boundary 56 of the housing 12 in order to restrict movement of the immobilization element 16 to the plane of movement.The immobilization element 16 also has a locking surface 58 facing the pawl 18 which is configured to engage with a projection 60 of the pawl 18 in order to fix the pawl 18 in an unlocked position (FIG. 6B ).Furthermore, the immobilization element 16 also has a guide flank 62, which is guided along a guide stop 64 of the housing 12 and comprises a straight first flank section 62 aand a straight second flank section 62 b, which are connected to one another by a bevel 62 cand which are formed such that the first flank section 62 amakes contact with the guide stop 64 when the immobilization element 16 is in the closed position (FIG. 6A ) and the second flank section 62 babuts contact with the guide stop 64 when the immobilization element 16 is in the overstroke position (FIG. 6C ).The guide channel 40 of the housing 12 running along the substantially triangular round section 14 forms a guide topology 66 and comprises an inner guide surface 68 and an outer guide surface 70 which delimit the guide channel 40 on the inside and on the outside, respectively. The guide topology 66 also comprises the ramp 44 formed in the guide channel 40, the height of which ramp increases in the direction of a movement direction 72 of the second pin 38.In the following, the mode of operation of the lock 10 is described with reference to FIGS. 5 and 6A to 6C. Any directional or positional information such as "clockwise", "upper", "lower", "right" and "left" is intended merely for simplified description of the mode of operation on the basis of the figures and is not intended to represent a limitation.In a position 1 (FIG. 6A ), the second pin 38 of the immobilization element 16 guided in the guide channel 40 is located in the right corner region of the round section 14. the pawl 18 assumes a locking position in which it rotatably locks the rotary latch 20 in the closed position. The striker 22 is securely held in the recess 24 of the rotary latch 18.If, by actuating a not-shown release lever, the pawl 18 is rotated clockwise about a pawl rotation axis 74 from its blocking position into its unlocking position, the rotary latch 20 is free to open, i.e. swivel open. The force required for pivoting the rotary latch 20 open is provided by the leg spring 52, which acts on the one hand on the rotary latch 20 and on the other hand on the third pin 46 and is prestressed in such a way that it moves the rotary latch 20 into an open position (see FIG. 6B ) as soon as the pawl 18 releases the rotary latch 20.As a result of the rotational movement of the rotary latch 20 from the closed position (FIG. 6A ) into the open position (FIG. 6B ), the driver 30 of the rotary latch 20 comes into contact with the first pin 34 of the immobilization element 16 and drives the immobilization element 16 with it until the second pin 38 is guided from the position 1 (FIG. 6A ) into a position 2 (FIG. 6B ). Between position 1 and position 2, the second pin 38 is guided over the ramp 44 with the tongue 42 springing out (cf. FIG. 5 ).In position 2 (FIG. 6B ), the immobilization element 16 locks the pawl 18 in the unlocking position. In this case, the immobilization element 16 is supported on the ramp 44 via the second pin 54. Ramp 44 prevents pawl 18 from pressing immobilizing element 16 back toward position 1 against predefined direction of movement 72 (FIG. 5 ). The striker 22 can disengage from the rotary latch 20 and the seat back can be folded over.If the backrest is re-erected, the striker 22 engages in the opened rotary latch 20 and presses or rotates it back into the closed position (FIG. 6C ). The leg spring 52 is tensioned in the process; at the same time, the immobilization element 16 is pressed from the position 2 downwards into a position 3 (cf. FIG. 5 ) and further into a position 4 (FIG. 6C ) by the striker 22 and the separating wall 36 of the rotary latch 20 located therebetween.At position 3, the immobilizing element 16 releases the pawl 18 so that it is moved back into the locked position by a spring, not shown. At position 3, the second pin 38 is located in the region, more precisely just in front of the lower left corner of the round section 14, but is still prevented from being pulled directly in the direction of position 1 by the leg spring 52.In position 4, i.e. in the lower left corner of the round section 14, the second pin 38 is released from the inner guide surface 68. At the same time, the immobilization element 16 comes into contact with the guide stop 64 and is moved back into the starting position or position 1 along the guide stop 64 by the leg spring 52 acting on the third pin 46. The overstroke produced between position 3 and position 4 ensures that the rotary latch 20 is first blocked and only then is the immobilization element 16 pulled back into the starting position.Finally, it should be pointed out that although a structure has been described here in which the guide topology 66 is provided on the housing 12 and the second pin 38 is formed on the immobilization element 16, it would conversely also be conceivable to implement the second pin 38 on the housing 12 and the guide topology 66 on the immobilization element 16.List of reference characters1 Position 1 2 Position 2 3 Position 3 4 Position 4 10 Lock 12 Housing 14 Round section 16 Immobilization element 18 Pawl 20 Rotary latch 22 Striker 24 Recess 26 Bearing bore 28 Bearing bolt 30 Driver 32 Receptacle 34 First pin 36 Separating wall 38 Second pin 40 Guide channel 42 Tongue 44 Ramp 46 Third pin 48 First arm 50 Link guide 52 Spring 54 Second arm 56 Boundary 58 Locking surface 60 Projection 62 Guide flank 64 Guide stop 66 Guide topology 68 Inner guide surface 70 Outer guide surface 72 Direction of movement 74 Axis of rotation of the pawl

Claims

Lock (10), in particular for a backrest of a motor vehicle, comprising a housing (12), a rotary latch (20) rotatably mounted in the housing (12), a pawl (18) for the rotary latch (20) and a immobilization element (16) for locking the pawl (18) in an unlocked position and immobilizing a striker accommodated in the rotary latch in a closed state of the lock, characterized in that the immobilization element (16) is driven by the rotary latch (20) and guided by a guide topology (66) exclusively in a predefined direction of movement (72) along a round section (14).Lock according to Claim 1, characterized in that the immobilization element (16) comprises an engagement feature, in particular a first pin (34), and the rotary latch has a driver (30) for carrying along the engagement feature.Lock according to Claim 1 or 2, characterized in that the guide topology (66) is formed in the housing (12) and accommodates a second pin (38) provided on the immobilization element (16), or the guide topology (66) is formed on the immobilization element (16) and accommodates a second pin (38) provided on the housing (12).Lock according to one of the preceding claims, characterized in that the guide topology (66) comprises an inner guide surface (68) and an outer guide surface (70), which together form a guide channel (40) for the second pin (38), said guide channel defining the round section (14).Lock according to one of the preceding claims, characterized in that the round section (14) describes at least approximately a triangle.Lock according to any one of the preceding claims, characterized in that the first pin (34) and the second pin (38) extend from opposite sides of the immobilizing element (16).Lock according to one of the preceding claims, characterized in that the guide topology (66) comprises a blocking element, in particular a ramp (44), which prevents the second pin (38) from being able to move counter to the predefined direction of movement (72).Lock according to claim 7, characterised in that the second pin (38) of the immobilizing element (16) is spring-mounted and / or the blocking element is flexible.Lock according to one of the preceding claims, characterized in that a preferably elastically deformable separating wall (36) is formed on the rotary latch (20), which separating wall prevents direct contact between a striker (22) engaging into the rotary latch (20) and the immobilization element (16).Lock according to one of the preceding claims, characterized in that the guide topology (66) comprises a guide stop (64) which is designed to limit the movement of the immobilization element (16) and / or to guide the movement of the immobilization element (16).Lock according to one of the preceding claims, characterized in that a spring (52) is connected between the rotary latch (20) and the immobilization element (16), which spring is tensioned into the closed position by a rotation of the rotary latch (20).Lock according to one of the preceding claims, characterized in that the immobilization element (16) is formed in one piece and / or has a second arm (54), which is guided by a boundary (56) on the housing side.Lock according to one of the preceding claims, characterized in that a first channel section of the guide topology (66) is designed, when the rotary latch (20) is opened, to guide the second pin (38) from a position 1 in which the immobilization element (16) is not engaged with the pawl (18) into a position 2 in which the immobilization element (16) and the pawl (18) are engaged and the pawl (18) is held in the unlocking position; a second channel section of the guide topology (66) is designed, when the rotary latch (20) is closed, to guide the second pin (38) from the position 2 into a position 3 in which the immobilization element (16) and the pawl (18) are disengaged again and the rotary latch (20) is locked by the pawl (18); the second channel section of the guide topology (66) is further configured, after the catch (20) is locked by the pawl (18) at the position 3, to guide the second pin (38) from the position 3 into a position 4 in which the immobilization element (16) is released in order to be able to be moved back into the position 1, in particular by a spring (52); and a third channel section of the guide topology (66) is configured to guide the second pin (38) from the position 4 into the position 1, wherein the immobilization element (16) is moved, in particular by the spring (52), from the position 4 into the position 1.Lock according to claim 13, characterised in that the positions 1, 2 and 4 represent corner points of a substantially triangular round section (14).

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