Lock mechanism for vehicle seats

Abstract

Lock mechanism (1) for vehicle seats that is used, for example, to lock the reclining backrest of the seat and comprises a rotary latch (7) moveable between an open position and a closed position, a first cam (15), a second cam (17) and a pre-compression system adapted to impart, to said cams (15, 17), such torques as to allow said cams (15, 17) to keep said rotary latch (7) in the closed position. Said pre- compression system consists of a spring assembly comprising a first coiled element (21a) and a second coiled element (21b), each associated with one of said cams (15, 17) and concentric to each other. The risk of interference between the two coiled elements is reduced and the assembling of the pre-compression system is easier.

Description

Lock mechanism for vehicle seats

[0001] The present invention relates to a lock mechanism used for locking a seat.

[0002] More particularly, the locking mechanism of the present invention finds application in the automotive field and can be used, by way of non-limiting example, to lock the reclining backrests of the rear seats present in a vehicle.

[0003] As is known, some of the currently circulating vehicles are equipped with rear seats whose backrests can be rotated between a first configuration, in which said backrests allow the rear seats to accommodate passengers, and a second configuration, in which said backrests are reclined on the rear seat cushions in order to expand the volume of the baggage compartment.

[0004] In said first configuration, the backrests of the rear seats must remain rigidly fastened to the vehicle structure to avoid unwanted and potentially dangerous seat movements while the vehicle is in motion. In said second configuration, instead, said backrest must be capable of being unfastened from the vehicle so that they can be reclined.

[0005] In order to be selectively fastened or unfastened, each backrest is provided with a lock mechanism suitable for engaging or disengaging a member of the vehicle structure, hereinafter referred to as locking striker.

[0006] A known lock mechanism is shown in.

[0007] Said lock mechanism, indicated with reference numeral 10, comprises a cover plate 20, a side plate 30 and a rotary latch 40 arranged between said plates and suitable for selectively holding or releasing the locking striker of the vehicle.

[0008] In particular, said rotary latch 40, rotating around a first bearing pin 50 fixed to the cover plate 20 and the side plate 30 can move from an open position, in which said rotary latch 40 and said locking striker do not cooperate with each other, thereby allowing to unfasten the vehicle backrest, to a closed position, in which said rotary latch 40 holds said locking striker, thereby keeping the backrest fastened to the vehicle.

[0009] As is known, said lock mechanism 10 further comprises a clamping cam 60 and a safety cam 70 that are capable of rotating side by side around a second bearing pin 80 parallel to said first bearing pin 50.

[0010] Once the closed position is reached, the combination of said clamping cam 60 and said safety cam 70 makes it possible to keep the rotary latch 40 in said closed position both under normal operating conditions and in the event of an accident, while at the same time allowing reducing the clearances caused by manufacturing and assembly tolerances.

[0011] In order to impart, to said clamping cam 60 and safety cam 70, a torque sufficient to hold said rotary latch 40 in said closed position, the lock mechanism 10 further comprises a pre-compression system acting on said cams.

[0012] In known lock mechanisms, said pre-compression system is often made by associating, to each of said cams 60, 70, a corresponding spring 61, 71.

[0013] Each of said springs 61, 71 is made as a torsion spring comprising a first end anchored to the cover plate 20, a coil portion surrounding said second bearing pin 80, and a second end suitable for interacting with the corresponding cam 60, 70.

[0014] A lock mechanism comprising such pre-compression system is known, for example, from document WO 2019 / 125327.

[0015] During assembly of the lock mechanism, 10, said springs 61, 71 are connected to the corresponding cams 60, 70 in a pre-compressed state so as to impart the required torque to said cams.

[0016] As can be seen from, said springs 61, 71 are partially inserted in each other, being eccentric to each other and to the rotation axis defined by the second bearing pin 80.

[0017] As a result, although the cover plate 20 may have a partial spacer 21 suitable for separating said springs 61, 71 in the region in which said springs are closer to each other, the proximity and eccentricity of said springs 61, 71 may cause said springs, during movement from the open position to the closed position and vice versa, to interfere with each other, this resulting, in extreme cases, in jamming of said springs, thereby making the mechanism unusable.

[0018] For this reason, known lock mechanisms are often configured to operate only within a limited range of rotation of said springs.

[0019] Furthermore, the eccentricity of said springs 61, 71 makes the force due to the torque imparted by said springs, i.e. the force applied by the cams 60, 70 to the rotary latch 40, change during rotation of said cams, thereby causing a change in the working conditions of the lock mechanism during this rotation.

[0020] In addition, the use and insertion of two different springs inside the lock mechanism inevitably brings about long assembly times and a risk of errors during assembly.

[0021] The main object of the present invention is to overcome the drawbacks mentioned above by providing a lock mechanism whose pre-compression system eliminates, or at least considerably reduces, the risk of interference between the coil portions acting on the clamping cam and the safety cam.

[0022] A further object of the present invention is to provide a pre-compression system that makes it possible to reduce the change in the force applied by the clamping cam and safety cam to the rotary latch during rotation of said cams.

[0023] A still further object of the present invention is to provide a pre-compression system that makes it possible to reduce lead times and the risk of errors in the assembly of the lock mechanism.

[0024] These and other objects are achieved with the lock mechanism as claimed in the appended claims.

[0025] The lock mechanism according to the invention comprises, in a manner known per se, a cover plate and a rotary latch, parallel to said cover plate and adapted to rotate around a first bearing pin in such a way as to move from an open position to a closed position and vice versa. Said lock mechanism further comprises a clamping cam, adapted to rotate around a second bearing pin parallel to said first bearing pin, a safety cam, also adapted to rotate around said second baring pin, and a pre-compression system adapted to impart such a first torque and second torque to said clamping cam and said safety cam, respectively, as to allow said cams to keep said rotary latch in the closed position (once said position has been reached).

[0026] According to the invention, said pre-compression system comprises a spring assembly adapted to interact with both the clamping cam and the safety cam.

[0027] Said spring assembly is inserted in the lock mechanism in such a way as to surround said second bearing pin.

[0028] Said spring assembly comprises a first coiled element, having a first winding radius, and a second coiled element, having a second winding radius, said first coiled element and said second coiled element being concentric to each other.

[0029] Preferably, the first winding radius is different from the second winding radius.

[0030] More preferably, the second winding radius is smaller than the first winding radius.

[0031] Even more preferably, the second coiled element is contained, at least partially, within the cylindrical volume defined by the first coiled element.

[0032] Still according to the invention, said spring assembly further comprises a first moveable leg, by means of which said first coiled element interacts with said clamping cam, and a second moveable leg, by means of which said second coiled element interacts with said safety cam.

[0033] According to a preferred embodiment of the invention, the spring assembly of the pre-compression system is made as a single spring adapted to interact with both said clamping cam and said safety cam.

[0034] Even more preferably, said single spring is made of a torsion spring comprising a first coiled portion, which constitutes said first coiled element, a second coiled portion, which constitutes said second coiled element, and a fixed leg adapted to connect said first coiled portion to said second coiled portion in such a way as to keep said first coiled portion and said second coiled portion concentric to each other.

[0035] Even more preferably, said first moveable leg is arranged at a first end of said torsion spring and / or said second moveable leg is arranged at a second end, opposite to said first end of said torsion spring.

[0036] Regardless of the embodiment, said cover plate comprises, according to the invention, a constraining portion for constraining said spring assembly to said cover plate.

[0037] The interaction between said spring assembly and said constraining portion makes the interaction between said first coiled element and said clamping cam and the interaction between said second coiled element and said safety cam independent of each other.

[0038] The method of assembling said pre-compression system within the lock mechanism therefore provides for the steps of:surrounding said second bearing pin by means of said first coiled element and said second coiled element;connecting said first coiled element to said clamping cam by means of said first moveable leg, thereby keeping said first coiled element in a pre-compressed state so that said first coiled element imparts the first torque to said clamping cam;connecting said second coiled element to said safety cam by means of said second moveable leg, thereby keeping said second coiled element in a pre-compressed state so that said second coiled element imparts the second torque to said safety cam.

[0039] Thanks to the geometry described above, the pre-compression system according to the invention makes it possible to considerably reduce the risk of interference between the two coiled elements during rotation of the clamping cam and safety cam, thereby increasing the reliability and strength of the lock mechanism even under extreme working conditions.

[0040] Furthermore, the assembly of the pre-compression system according to the present invention, especially when a single torsion spring is provided, is considerably simplified compared to the assembly of known pre-compression systems, leading to a remarkable reduction in assembly times and avoiding the risk of errors.

[0041] Preferably, said first coiled element and said second coiled element surround the second bearing pin in such a way that said first coiled element and said second coiled element are concentric to the axis of said second bearing pin, i.e. to the rotation axis of the clamping cam and safety cam.

[0042] In this way, advantageously, said first coiled element and said second coiled element always work at the same distance from said rotation axis; therefore, the force generated by the torques applied by said first coiled element and said second coiled element to the clamping cam and the safety cam, respectively, does not change during rotation of said cams.

[0043] This makes it possible to keep the working conditions of the lock mechanism constant.

[0044] In a preferred embodiment of the invention, when the second winding radius differs from the first winding radius, the constraining portion provided on the cover plate can be made as an annular spacer interposed between the first coiled element and the second coiled element.

[0045] Advantageously, the presence of said annular spacer separating the first coiled element from the second coiled element further reduces the risk of interference between the two coiled elements during rotation of the cams.

[0046] Even more preferably, when the spring assembly is made as a single torsion spring and the first winding radius of the first coil portion is different from the second winding radius of the second coil portion, the annular spacer that separates the first coil portion from the second coil portion is provided with a slot adapted to accommodate the fixed leg of said torsion spring.

[0047] According to a further aspect of the present invention, the rotary latch of the lock mechanism comprises one or more bodies and one or more covers suitable for surrounding, either partially or completely, said one or more bodies.

[0048] According to a first preferred embodiment, said one or more bodies and said one or more covers are joined to one another by means of one or more snap-on fastenings and / or by providing, on each of said bodies and said covers, appropriate openings / recesses adapted to mate with corresponding protruding portions defined on the adjacent bodies and covers.

[0049] The term 'snap-on fastening' means the joining of two components of which one component (preferably one of said one or more covers) has an appendix having a shape such as to allow said appendix to be fastened to (by automatically snapping on) a corresponding coupling surface provided on a second component (preferably one of said one or more bodies).

[0050] Preferably, said openings / recesses can be made as holes and said protruding portions can be made as pins.

[0051] Preferably, said one or more covers are connected to said one or more bodies in such a way that they can later be disassembled from said one or more bodies.

[0052] According to a second preferred embodiment, said one or more covers are applied to said one or more bodies by an overmolding process.

[0053] The joining process using snap-on fastenings and openings / recesses combined with protruding portions differs from the overmolding process in that it allows, firstly, precise positioning and alignment of said bodies and said covers during assembly and, secondly, does not involve any heat release, allowing said bodies to be joined together with said covers without thermal distortions being created on these elements.

[0054] On the other hand, the overmolding process reduces assembly times and allows these covers to be applied even to complex shaped bodies.

[0055] Regardless of the embodiment, when said rotary latch comprises more than one body, said bodies are preferably joined to each other by means of one or more snap-on fastenings and / or by providing, on each of said bodies and said covers, appropriate openings / recesses adapted to mate with corresponding protruding portions defined on the adjacent bodies

[0056] Preferably, even in this case said openings / recesses can be made as holes and said protruding portions can be made as pins.

[0057] According to a further aspect of the present invention, said rotary latch comprises a first stop surface adapted to interact with a second stop surface of said cover plate to stop rotation of said rotary latch in a direction from the closed position to the open position.

[0058] Said first stop surface and said second stop surface are shaped in such a way that the force generated by the contact between said surfaces is tangent to the rotation diameter of said rotary latch.

[0059] In this way, only a force useful for stopping the rotary latch is generated, with no force normal to the diameter of rotation, which could compromise the functionality of the lock mechanism.

[0060] According to a further aspect of the present invention, said lock mechanism comprises a side plate, parallel to the cover plate. Said side plate comprises:a third bearing hole, adapted to accommodate the first bearing pin in such a way as to fix said first bearing pin to said side plate;a fourth bearing hole, adapted to accommodate the second bearing pin in such a way as to fix said second bearing pin to said side plate;a first face;a second face, opposite to said first face;first embossed portions protruding from said first face and arranged around said third bearing hole in such a way as to lie on a first circumference concentric to said third bearing hole;second embossed portions protruding from said second face and arranged around said third bearing hole in such a way as to lie on said first circumference;third embossed portions protruding from said first face and arranged around said fourth bearing hole in such a way as to lie on a second circumference concentric to said fourth bearing hole;fourth embossed portions protruding from said second face and arranged around said fourth bearing hole in such a way as to lie on said second circumference.

[0061] Advantageously, said side plate can be used interchangeably in both the lock mechanisms associated with the right-hand backrests and the lock mechanisms associated with the left-hand backrests.

[0062] Preferably, said first and second embossed portions are arranged alternately on said circumference and said third and fourth embossed portions are arranged alternately on said second circumference.

[0063] Preferably, said first circumference and said second circumference have the same diameter.

[0064] Preferably, the first and third embossed portions on the first face are associated with corresponding recesses on the second face.

[0065] Similarly, the second and fourth embossed portions on the second face are associated with corresponding recesses on the first face.

[0066] Further features and advantages of the present invention will become evident from the following detailed description of a preferred embodiment of the invention, given by way of non-limiting example with reference to the annexed drawings, in which:Fig.1

[0067] shows a lock mechanism of known type;Fig.2

[0068] shows a pre-compression system of known type;Fig.3

[0069] shows a lock mechanism according to the invention;Fig.4

[0070] shows a pre-compression system according to the invention;Fig.5

[0071] shows the pre-compression system ofassociated with the clamping cam and the safety cam of the lock mechanism of;Fig.6

[0072] shows the pre-compression system ofassociated with the cover plate of the lock mechanism of;Fig.7

[0073] shows the rotary latch of the lock mechanism ofaccording to a first embodiment;Fig.8

[0074] shows the rotary latch of the lock mechanism ofaccording to a second embodiment;Fig.9

[0075] shows a detail of a sectional view of the rotary latch of;Fig.10

[0076] shows the rotary latch of the lock mechanism ofaccording to a third embodiment;Fig.11

[0077] shows the rotary latch ofassociated with the cover plate of;Fig.12

[0078] shows the side plate of the lock mechanism of.

[0079] In the following description of some preferred embodiments of a lock mechanism, reference will be made to a lock mechanism mounted in a vehicle and used to selectively lock the reclining backrest of one of the rear seats to the vehicle structure.

[0080] A lock mechanism according to the present invention is shown inand is indicated with reference numeral 1.

[0081] In this case, the lock mechanism 1 is fastened, in use, to the backrest of one of the rear seats and is adapted to lock a locking striker (not shown), usually having a ring-like shape, fastened to the vehicle structure.

[0082] Alternatively, it would also be possible to provide a lock mechanism fastened to the vehicle structure and a locking striker fastened to the backrest.

[0083] Said lock mechanism 1 comprises a cover plate 3, provided with a first bearing hole 3a and a second bearing hole 3b, and a side plate 5, provided with a third bearing hole 5a and a fourth bearing hole 5b.

[0084] A first groove 3c is defined in the cover plate 3 and a second groove 5c is defined in the side plate 5, said grooves being adapted to receive, in use, said locking striker (in particular during locking of the backrest to the vehicle structure).

[0085] Said lock mechanism 1 further comprises a rotary latch 7, adapted to rotate around a first bearing pin 9. To this aim, the rotary latch 7 comprises a hole 7a through which the first bearing pin 9 extends.

[0086] Said first bearing pin 9 is fixed to the cover plate 3 and the side plate 5; in particular, the first bearing pin 9 is inserted in said first bearing hole 3a of the cover plate 3 and in said third bearing hole 5a of the side plate 5 and extends perpendicularly to said cover plate 3 and said side plate 5.

[0087] The rotary latch 7 further comprises a hook-like opening 7b adapted to cooperate, in use, with the locking striker.

[0088] In particular, said rotary latch 7, rotating around said first bearing pin 9, is adapted to move from a first open position, in which said rotary latch 7 and said locking striker do not cooperate with each other and the backrest is unfastened from the vehicle structure, to a closed position, in which said locking striker is constrained by the cooperation between said hook-like opening 7b and the receiving grooves 3c and 5c of said cover plate 3 and said side plate 5, thereby keeping the backrest fastened to the vehicle.

[0089] A first spring 11, made as a torsion spring, acts on said rotary latch 7 in such a way that, when said rotary latch 7 is not cooperating with the locking striker, said rotary latch 7 automatically returns to the open position.

[0090] Said lock mechanism 1 further comprises a second bearing pin 13, parallel to said first bearing pin 9 and inserted in the second bearing hole 3b of the cover plate 3 and the fourth bearing hole 5b of the side plate 5.

[0091] A clamping cam 15 and a safety cam 17 are adapted to rotate side by side on said second bearing pin 13. For this purpose, said clamping cam 15 has a hole 15’ through which said second bearing pin 13 extends, and said safety cam 17 has a hole 17’ through which said second bearing pin 13 extends.

[0092] Said clamping cam 15 and said safety cam 17 interact with the rotary latch 7, applying, to said rotary latch 7, a force such as to keep said rotary latch in the closed position once said position has been reached, thereby overcoming the action of the first spring 11.

[0093] In order for this to be possible, said clamping cam 15 and said safety cam 17 are associated to an appropriate pre-compression system, adapted to impart such a first torque and a second torque to said cams, respectively, as to generate the force necessary to keep the rotary latch 7 in the closed position.

[0094] According to a preferred embodiment of the invention illustrated in Figures 3 - 6, said pre-compression system comprises a second spring 21 adapted to interact with both said clamping cam 15 and said safety cam 17 to impart the required torque to each of said cams.

[0095] As can be seen from Figures 4 and 5, said second spring 21 is a torsion spring comprising:a first coil portion 21a, adapted to surround said second bearing pin 13 with a first winding radius Ra;a second coil portion 21b, adapted to surround said second bearing pin 13 with a second winding radius Rb smaller than the first winding radius Ra;a fixed leg 21c adapted to connect said first coil portion 21a to said second coil portion 21b in such a way that said first coil portion 21a and said second coil portion 21b are concentric to each other and lie on a same plane;a first moveable leg 21d, made as a hook arranged at a first end of said second spring 21 and adapted to hook on clamping protrusion 15a of said clamping cam 15; anda second moveable leg 21e, made as a hook arranged at a second end, opposite to said first end, of said second spring 21 and adapted to hook on a safety protrusion 17a of said safety cam 17.

[0096] By means of said first moveable leg 21d, said first coil portion 21a interacts with the clamping cam 15, allowing said first coil portion 21a to apply the first torque to said clamping cam 15.

[0097] Similarly, by means of said second moveable leg 21c, said second coil portion 21b interacts with the safety cam 17, allowing said second coil portion 21b to apply the second torque to said safety cam 17.

[0098] The configuration of said second spring 21, comprising two concentric coil portions 21a and 21b spaced from each other, makes it possible to considerably reduce the risk of interference between said coil portions during rotation of the clamping cam 15 and the safety cam 17 compared to known lock mechanisms.

[0099] Alternatively, said first coil portion 21a and said second coil portion 21b, though being concentric to each other, might take different configurations. For instance, the second winding radius Rb might be larger than the first winding radius Ra and / or the first coil portion 21a and the second coil portion 21b might lie on different planes.

[0100] As can be seen from Figures 5 and 6, said first coil portion 21a and said second coil portion 21b, besides being concentric to each other, are also concentric to the axis of said second bearing pin 13, corresponding to the axis of the first bearing hole 3a and to the rotation axis of the clamping cam 15 and safety cam 17.

[0101] Therefore, during rotation of said cams, said first coil portion 21a and said second coil portion 21b always work at the same distance from said axis. Accordingly, the force generated by the overall torque applied by said first coil portion 21a and said second coil portion 21b to the clamping cam 15 and safety cam 17, respectively, does not change during rotation of said cams.

[0102] This also means that the force exerted by the rotary latch 7 against the overall torque generated by the two coil portions undergoes, during rotation of the rotary latch 7, a change that is remarkably reduced compared to known lock mechanisms.

[0103] Still referring to, said cover plate 3 comprises a annular spacer 3c interposed between said first coil portion 21a and said second coil portion 21b and provided with a slot 3c’ adapted to accommodate said fixed leg 21c.

[0104] By inserting said fixed leg 21c in said slot 3c’ it is possible to constrain said second spring 21 to said cover plate 3, thereby making the interaction between said first coil portion 21a and said clamping cam 15 and the interaction between said second coil portion 21b and said safety cam 17 independent of each other.

[0105] Furthermore, the presence of said annular spacer separating said first coil portion 21a from said second coil portion 21b further reduces the risk of interference between said coil portions during rotation of the clamping cam 15 and the safety cam 17.

[0106] Therefore, the method of assembling said second spring 21 within the lock mechanism provides for the steps of:arranging said second spring 21 on the cover plate 3 in such a way that said first coil portion 21a and said second coil portion 21b are coaxial to the first bearing hole 3a;inserting said fixed leg 21c into the slot 3c’ of the annular spacer 3c in such a way that said annular spacer 3c is interposed between said first coil portion 21a and said second coil portion 21b;connecting said first moveable leg 21d to the clamping protrusion 15a of said clamping cam 15, thereby keeping said first coil portion 21a in a pre-compressed state so that said first coil portion 21a imparts the first torque to said clamping cam 15;connecting said second moveable leg 21e to the safety protrusion 17a of said safety cam 17, thereby keeping said second coil portion 21b in a pre-compressed state so that said second coil portion 21b imparts the second torque to said safety cam 17.

[0107] It is evident to the person skilled in the art that, in an alternative embodiment of the invention, a pre-compression system comprising a first coil portion and a second coil portion made as two separate and concentric elements can be provided, the overall construction and operation of the pre-compression system being the same as described above.

[0108] According to a further aspect of the present invention, the rotary latch 7 of the lock mechanism 1 comprises one or more bodies and one or more covers suitable for surrounding, either partially or completely, said one or more bodies.

[0109] The combination of said one or more bodies and said one or more covers defines the overall shape of the rotary latch 7.

[0110] Preferably, said bodies and said covers are joined to one another by means of one or more snap-on fastenings and / or by providing, on each of said bodies and said covers, appropriate openings / recesses adapted to mate with corresponding protruding portions defined on the adjacent bodies and covers.

[0111] The term 'snap-on fastening' means the joining of two components of which one component (preferably one of said one or more covers) has an appendix having a shape such as to allow said appendix to be fastened to (by automatically snapping on) a corresponding coupling surface provided on a second component (preferably one of said one or more bodies).

[0112] Preferably, said openings / recesses can be made as holes and said protruding portions can be made as pins.

[0113] Advantageously, the use of snap-on fastenings and openings / recesses combined with protruding portions allows not only joining of said bodies and said covers, but also precise positioning and alignment of these components relative to one another.

[0114] In addition, this type of joining, unlike the welding or overmoulding techniques, does not involve any heat release allowing these bodies to be joined together with these covers without thermal distortions being created on these elements.

[0115] Even more preferably, said one or more covers are connected to said one or more bodies in such a way that they can later be disassembled from said one or more bodies.

[0116] This advantageously makes it possible to easily remove and replace said one or more covers in the event that they are defective.

[0117] When, on the other hand, said one or more covers are applied to said one or more bodies by means of an overmoulding process, these covers can no longer be removed. This means that, if a problem occurs during the overmoulding process of these covers, both the covers and the bodies on which the covers have been overmoulded must be discarded, or it is necessary to carry out a further process to remove the covers from the bodies.

[0118] According to a first preferred embodiment of the present invention, shown in, the rotary latch 7 consists of a body 8a and a cover 8b.

[0119] In particular, said body 8a has two pins 8a’ and 8a’’ adapted to be inserted in corresponding holes 8b’ and 8b’’, respectively, provided on the cover 8b, so as to join, and simultaneously align, said cover 8b to said body 8a.

[0120] As can be seen from, said cover 8b defines a portion of the hook-like opening 7b of the rotary latch 7. As the hook-like opening 7b is the part adapted to hold the locking striker, it is possible, depending on the shape and size of the locking striker, to mount different covers 8b on said body 8a, thereby allowing the rotary latch 7 to be adapted to different locking strikers simply by changing said cover 8b.

[0121] According to a second preferred embodiment of the present invention, as can be seen from, said rotary latch 7 consists of a first body 8a, a second body 8c and a cover 8d.

[0122] Said first body 8a, corresponding to the body described in the first embodiment, comprises a first pin 8a’ and a second pin 8a’’.

[0123] Said cover 8d comprises a first pin 8d’ and a second pin 8d’’.

[0124] Said second body 8c, parallel to said first body 8a and interposed between said first body 8a and said cover 8d, comprises a first through-hole 8c’ and a second through-hole 8c’’, each of said through-holes therefore having a first opening facing said first body 8a and a second opening, opposite to said first opening, facing said cover 8d.

[0125] The first pin 8a’ of said first body 8a is inserted in said first through-hole 8c’ through the first opening of said hole and said first pin 8d’ of said cover 8d is inserted in said first through-hole 8c’ through the second opening of said hole.

[0126] The second pin 8a’’ of said first body 8a is inserted in said second through-hole 8c’’ through the first opening of said hole and said second pin 8d’’ of said cover 8d is inserted in said second through-hole 8c’’ through the second opening of said hole.

[0127] In particular, said first body 8a and said second body 8c are joined, preferably, by means of a staking joining process of the pins 8a’ and 8a’’ of the first body 8a in the corresponding through-holes 8c’ and 8c’’ of said second body 8c.

[0128] Furthermore, said first body 8a, said second body 8c and said cover 8d are joined to one another by snap-on fastening.

[0129] As can be seen from, which shows a partial section of the rotary latch 7 in said second embodiment, said snap-on fastening consists in the interaction between an appendix 8d’’’, with ‘L’-shaped cross section, of said cover 8d and a coupling surface 8a’’’ of said first body 8a. In particular, said appendix 8d’’’ is adapted for being fastened to said coupling surface 8a’’’ in such a way that the first body 8a, the cover 8d and the second body 8c interposed therebetween are kept joined to one another.

[0130] Although the union of said one or more bodies and said one or more covers by means of snap-on fastenings and / or by the combination of openings / recesses and protruding portions has the above-mentioned advantages, it is not excluded that in the rotary latch of the present invention said one or more covers may be applied to said one or more bodies by overmolding, as shown in a third embodiment of the present invention, illustrated in.

[0131] In this third embodiment, the rotary latch 7, similarly to the second embodiment, comprises a first body 8a, a second body 8c, and a cover 8d.

[0132] Also similarly to the second embodiment, said first body 8a and said second body 8c are joined together by inserting pins, located on the first body 8a / second body 8c, into corresponding holes, located on the second body 8c / first body 8a.

[0133] Contrary to the second embodiment, cover 8d is applied to said first body 8a and said second body 8c by means of an overmolding process, after which cover 8d partially covers first body 8a and second body 8c.

[0134] However, in an alternative embodiment, as a result of the overmolding process, said cover 8d could completely cover the first body 8a and the second body 8c.

[0135] The overmolding process offers the advantage of being able to quickly and effectively coat even complex shaped bodies, such as the first body 8a of said third embodiment.

[0136] In particular, in this third embodiment, the first body 8a has a holed portion 8f which, by means of overmolding, can be partially or completely covered by the cover 8d.

[0137] Furthermore, thanks to the overmolding process, it is also possible to strengthen the union between the first body 8a and the second body 8c.

[0138] In the second and third embodiments, both the first body 8a and the second body 8c could, alternatively, be provided with holes arranged in such a way that, when the second body 8c is placed next to the first body 8a, the holes in said first and second bodies are aligned. In this case, said first and second bodies 8a, 8c could be joined together by inserting pins into said aligned holes.

[0139] Furthermore, in the second and third embodiments, said first body 8a and said second body 8c could be joined together by other techniques, such as snap-on fastening, welding or overmolding.

[0140] When comparing the first embodiment with the second and third embodiment, it can be noted that, advantageously, starting from the first body 8a with thickness Sa, it is possible to increase the overall thickness S of the rotary latch 7 and thus increase the performance of the lock mechanism 1 simply by joining the second body 8c with thickness Sc to said first body 8a.

[0141] Therefore, it is possible to adapt the rotary latch 7 to the required performance simply by adding or removing one or more of said bodies.

[0142] As shown in Figures 8 and 10, said second body 8c can, preferably, be shaped to increase the overall thickness S of the rotary latch 7 at those regions where the rotary latch 7 is most stressed during use.

[0143] Therefore, said second body 8c can have a footprint (perpendicular to the rotation axis of the rotary latch 7) smaller than the footprint of said first body 8a, which substantially corresponds to the footprint of the rotary latch 7.

[0144] As a result, by introducing said second body 8c, it is possible to achieve an increase in the performance of the lock mechanism 1 without having to considerably increase the volume or weight of the rotary latch 7.

[0145] In an alternative embodiment, the rotary latch 7 could also comprise further bodies in addition to said first body 8a and second body 8c, said further bodies preferably being arranged in such a way as to increase the overall thickness S of the rotary latch 7.

[0146] Even in this case, said further bodies could have a smaller footprint than the footprint of the first body 8a.

[0147] According to another aspect of the present invention, said rotary latch 7 comprises, in a known manner, a first stop surface adapted to interact with a second stop surface provided on the cover plate 3.

[0148] During rotation of the rotary latch 7 from the closed position to the open position, said first stop surface of the rotary latch 7 approaches said second stop surface of the cover plate 3 until it abuts against said second stop surface. When this occurs, the second stop surface, acting as an end stop for the rotary latch7, prevents further rotation of said rotary latch 7.

[0149] In known lock mechanisms, the contact force generated by the interaction between said first stop surface and said second stop surface has not only a component tangent to the rotation diameter of the rotary latch, which causes the rotary latch 7 to stop, but also a component normal to said diameter, which may jeopardize the functionality of the lock mechanism.

[0150] In the lock mechanism of the present invention 1, instead, said first stop surface and said second stop surface are shaped in such a way that the force generated by the contact between said first stop surface and said second stop surface is tangent to the rotation diameter of the rotary latch 7 and free of components normal to this direction.

[0151] According to a preferred embodiment, shown in, the rotary latch 7 comprises a cover 8d (similar to the one described inor) provided with a first stop surface 8e adapted to interact with a second stop surface 3d provided on said cover plate 3 (visible in).

[0152] Alternatively, said first stop surface 8e could be defined on any cover, such as, for example, the cover 8b described in, or on any body forming said rotary latch 7.

[0153] As can be seen from, said first stop surface 8e and said second stop surface 3d are oriented along the radial direction defined by the rotation axis of the rotary latch 7.

[0154] This makes it possible, advantageously, to obtain a contact force F perpendicular to said radial direction and thus totally tangent to the rotation diameter of the rotary latch 7.

[0155] According to another aspect of the present invention, the side plate 5 of the lock mechanism 1 according to the invention comprises, in a known manner, a first face 5d, a second face 5e, opposite to said first face 5d, and embossed portions adapted to interact with the rotary latch 7 and the safety cam 17.

[0156] In known lock mechanisms, the side plate has two embossed portions, both arranged on the face of the side plate facing the rotary latch and the safety cam, each embossed portion being adapted to surround the bearing holes of said side plate.

[0157] The arrangement of said two embossed portions on a single face of the side plate, in combination with the arrangement of the bearing holes makes the side plate of the lock mechanisms associated with the right-hand backrests (hereinafter referred to as 'right-hand mechanisms') differ from the side plate used in the lock mechanisms associated with the left-hand backrests (hereinafter referred to as 'left-hand mechanisms').

[0158] Therefore, the side plate of the right-hand mechanisms is non interchangeable with the side plate of the left-hand mechanisms. Accordingly, it is necessary to provide a large number of components in order to manufacture both the right-hand mechanisms and the left-hand mechanisms.

[0159] The side plate 5 of the lock mechanism 1 according to the present invention, instead, can be used indifferently for both the right-hand mechanisms and the left-hand mechanisms, as it comprises embossed portions arranged both on the first face 5d and the second face 5e.

[0160] In particular, as can be seen from, said side plate 5 comprises:first embossed portions 5a’ protruding from the first face 5d and arranged around the third bearing hole 5a in such a way as to lie on a first circumference 5f concentric to said third bearing hole 5a;second embossed portions 5a’’ protruding from the second face 5e and arranged around the third bearing hole 5a in such a way as to lie on said first circumference 5f;third embossed portions 5b’ protruding from the first face 5d and arranged around the fourth bearing hole 5b in such a way as to lie on a second circumference 5g concentric to said fourth bearing hole 5b;fourth embossed portions 5b’’ protruding from the second face 5e and arranged around the fourth bearing hole 5b in such a way as to lie on said second circumference 5g.

[0161] This configuration of the embossed portions allows:in the right-hand mechanisms, positioning the side plate 5 with the first face 5d facing the rotary latch 7 and the safety cam 17 in such a way that said first embossed portions 5a’ and said third embossed portions 5b’ interact with said rotary latch 7 and said safety cam 17;in the left-hand mechanisms, positioning the side plate 5 with the second face 5e facing the rotary latch 7 and the safety cam 17 in such a way that said second embossed portions 5a’’ and said fourth embossed portions 5b’’ interact with said rotary latch 7 and the safety cam 17.

[0162] Preferably, said first embossed portions 5a’ and said second embossed portions 5a’’ are arranged alternately on said circumference 5f and said third embossed portions 5b’ and said fourth embossed portions 5b’’ are arranged alternately on said second circumference 5g.

[0163] Preferably, said first circumference 5f and said second circumference 5g have the same diameter.

[0164] Preferably, said embossed portions of the side plate 5 are circular.

[0165] Preferably, the first embossed portions 5a’ and the third embossed portions 5b’ on the first face 5d are associated with corresponding recesses on the second face 5e.

[0166] Similarly, the second embossed portions 5a’’ and the fourth embossed portions 5b’’ on the second face 5e are associated with corresponding recesses on the first face 5d.

[0167] In addition, the side plate 5 according to the invention makes it possible, advantageously, to reduce the contact surfaces between the embossed portions, the rotary latch 7 and the safety cam 17.

[0168] It will be evident to the person skilled in the art that the embodiments described in detail above are in no way to be understood in a limiting sense, and that numerous variations and modifications are possible without thereby departing from the scope of the invention as defined by the appended claims.

[0169] It will further be evident to the person skilled in the art that, although the lock mechanism finds particular application to vehicle seats, and especially for locking the reclining backrest of a vehicle seat, other applications and uses cannot be excluded.

Claims

Lock mechanism (1) for vehicle seats, comprising:a cover plate (3);a rotary latch (7), parallel to said cover plate (3) and adapted to rotate around a first bearing pin (9) fixed to said cover plate (3) in such a way as to move from a first position, or open position, to a second position, or closed position, and vice versa;a clamping cam (15), adapted to rotate around a second bearing pin (13), fixed to said cover plate and parallel to said first bearing pin (9), and for interacting with said rotary latch (7);a safety cam (17), adapted to rotate around said second bearing pin (13) and interact with said rotary latch (7); anda pre-compression system, adapted to impart such a first torque and a second torque to said clamping cam (15) and said safety cam (17), respectively, as to allow said clamping cam (15) and said safety cam (17) to keep said rotary latch (7) in the closed position once said position has been reached;characterised in that:said pre-compression system comprises a spring assembly adapted to interact with both the clamping cam (15) and the safety cam (17), said spring assembly including:a first coiled element (21a) adapted to surround said second bearing pin (13) with a first winding radius (Ra);a second coiled element (21b) arranged to surround said second bearing pin (13) with a second winding radius (Rb), said first coiled element (21a) and said second coiled element (21b) being concentric to each other;a first moveable leg (21d), by means of which said first coiled element (21a) interacts with said clamping cam (15) in such a way as to impart said torque to said clamping cam (15); anda second moveable leg (21e), by means of which said second coiled element (21b) interacts with said safety cam (17) in such a way as to impart said second torque to said safety cam (17);said cover plate (3) comprises a constraining portion (3c) for constraining said spring assembly to said cover plate (3).Lock mechanism (1) according to claim 1, wherein said second winding radius (Rb) is different from said first winding radius (Ra) and is preferably smaller than said first winding radius (Ra).Lock mechanism (1) according to claim 1 or 2, wherein said second coiled element (21b) is contained, at least partially, within the cylindrical volume defined by the first coiled element (21a).Lock mechanism (1) according to any one of the preceding claims, wherein said first coiled element (21a) and said second coiled element (21b) are adapted to surround said second bearing pin (13) in such a way that said first coiled element (21a) and said second coiled element (21b) are concentric to the rotation axis of said clamping cam (15) and said safety cam (17).Lock mechanism (1) according to claim 3, wherein said constraining portion (3c) is made as an annular spacer interposed between said first coiled element (21a) and said second coiled element (21b).Lock mechanism (1) according to any one of the preceding claims, wherein said rotary latch (7) comprises one or more bodies (8a; 8a, 8c) surrounded, either partially or completely, by one or more covers (8b; 8d), said one or more bodies (8a; 8a, 8c) and said one or more covers (8b; 8d) being joined to one another by means of one or more snap-on fastenings and / or by providing, on said one or more bodies (8a; 8a, 8c) and on said one or more covers (8b; 8d), openings / recesses adapted to mate with corresponding protruding portions defined on the adjacent bodies and covers.Lock mechanism (1) according to any one of the claims 1 – 5, wherein said rotary latch (7) comprises one or more bodies (8a, 8c) surrounded, either partially or completely, by one or more covers (8d), and wherein said one or more covers (8d) are overmolded on said one or more bodies (8a, 8c).Lock mechanism (1) according to claim 6 or 7, wherein said rotary latch (7) comprises a plurality of bodies (8a, 8c), the bodies (8a, 8c) of said plurality of bodies being joined to one another by means of one or more snap-on fastenings and / or by providing on said bodies (8a, 8c) openings / recesses adapted to mate with corresponding protruding portions defined on the adjacent bodies.Lock mechanism (1) according to claim 6 or 8, wherein said openings / recesses are made as holes and said protruding portions are made as pins.Lock mechanism (1) according to claim 6, wherein said rotary latch (7) consists of a body (8a) and a cover (8b), said body (8a) comprising two pins (8a’) and (8a’’) adapted to be inserted in corresponding holes (8b’) and (8b’’), respectively, provided on the cover (8b).Lock mechanism (1) according to claim 9 when dependent on claim 6, wherein said rotary latch (7) consists of:a first body (8a), comprising a first pin (8a’) and a second pin (8a’’);a cover (8d), comprising a first pin (8d’) and a second pin (8d’’);a second body (8c), parallel to said first body (8a) and interposed between said first body (8a) and said cover (8d), said second body comprising a first through-hole (8c’) and a second through-hole (8c’’), said through-holes (8c’, 8c’’) being adapted to receive said pins (8a’, 8a’’) of said first body (8a) and said pins (8d’, 8d’’) of said cover (8d), and wherein said cover (8d) comprises an appendix (8d’’’) with ‘L’-shaped cross-section adapted to be fastened to a coupling surface (8a’’’) of said body (8a) in such a way as to realize a fastening suitable for keeping said first body (8a), said cover (8d) and said second body (8c) joined to one another.Lock mechanism (1) according to claim 9 when dependent on claim 8, wherein said rotary latch (7) consists of a first body (8a), a second body (8c) and a cover (8d), wherein said first body (8a) / second body (8c) are provided with pins designed to be inserted into corresponding holes in said second body (8c) / first body (8a), and wherein said cover (8d) is overmolded onto said first body (8a) and second body (8c).Lock mechanism (1) according to claim 11 or 12, wherein said second body (8c) has a footprint, meaning the surface perpendicular to the rotation axis of said rotary latch (7), smaller than the footprint of said first body (8a), and wherein the footprint of said first body (8a) substantially corresponds to the footprint of said rotary latch (7).Lock mechanism (1) according to any one of the preceding claims, wherein said rotary latch (7) comprises a first stop surface (8e) adapted to interact with a second stop surface (3d) of said cover plate (3) to stop rotation of said rotary latch (7) in a direction from the closed position to the open position, and wherein said first stop surface (8e) and said second stop surface (3d) are shaped in such a way that the force generated by the contact between said first stop surface (8e) and said second stop surface (3d) is tangent to the rotation diameter of said rotary latch (7).Lock mechanism (1) according to any one of the preceding claims, wherein said lock mechanism (1) comprises a side plate (5) parallel to said cover plate (3) and comprising:a third bearing hole (5a), adapted to accommodate the first bearing pin (9) in such a way as to fix said first bearing pin (9) to said side plate (5);a fourth bearing hole (5b), adapted to accommodate the second bearing pin (13) in such a way as to fix said second bearing pin (13) to said side plate (5);a first face (5d);a second face (5e), opposite to said first face (5d);first embossed portions (5a’) protruding from said first face (5d) and arranged around said third bearing hole (5a) in such a way as to lie on a first circumference (5f) concentric to said third bearing hole (5a);second embossed portions (5a’’) protruding from said second face (5e) and arranged around said third bearing hole (5a) in such a way as to lie on said first circumference (5f);third embossed portions (5b’) protruding from said first face (5d) and arranged around said fourth bearing hole (5b) in such a way as to lie on a second circumference (5g) concentric to said fourth bearing hole (5b);fourth embossed portions (5b’’) protruding from said second face (5e) and arranged around said fourth bearing hole (5b) in such a way as to lie on said second circumference (5g).Method of assembling a pre-compression system in a lock mechanism (1) according to any one of claims 1-15, comprising the steps of:surrounding said second bearing pin (13) by means of said first coiled element (21a) and said second coiled element (21b);connecting said first coiled element (21a) to said clamping cam (15) by means of said first moveable leg (21d), thereby keeping said first coiled element (21a) in a pre-compressed state;connecting said second coiled element (21b) to said safety cam (17) by means of said second moveable leg (21e), thereby keeping said second coiled element (21b) in a pre-compressed state.

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