FR2821380A1 - Door lock with half-turn bolt comprises rollback activated by door handle which acts on bolt tail to lead bolt head inside casing when handle is operated - Google Patents

Abstract

The door lock comprises a casing (3), a half-turn bolt, a spring acting on the bolt in a position where the bolt head (5a) projects partially outside the casing. A rollback (6) activated by a door handle comprises a rollback arm (33) able to act on the bolt tail (5b) to lead the bolt head inside the casing when the user acts on the door handle. The rollback and the rollback arm are made from separate parts (105,106) which can be rotated around a common axis. A de-clutchable coupling (107) is arranged between the rollback and the rollback arm.

Description

<Desc / Clms Page number 1>

 The present invention relates to a door lock, of the type comprising: a) a housing, b) a latch bolt having a head and a tail, which is guided and movable in horizontal translation in the housing, c) a spring biasing the latch bolt in an extended position in which the head of the latch bolt projects partially out of the housing, d) a nut intended to be actuated by a door handle and comprising a nut arm capable of acting on the tail of the latch to turn the head of the latter into a retracted position inside the housing when a user acts on the door handle, and optionally e) a deadbolt having a head and a tail, which is guided and movable in horizontal translation in the housing between a retracted position and an extended position, f) at least one control part, which is connected or connectable to at least one control rod for at least one additional deadbolt ha ut or bottom located outside the housing, and which is guided and movable in vertical translation in the housing between a first and a second position corresponding respectively to an unlocking position and an additional locking bolt locking position, g) a lock cylinder carried by the housing and comprising a bit which can be actuated by means of an appropriate key, and h) a transmission mechanism which is in drive relation with the bit of the lock cylinder and with the tail of the latch bolt, the tail of the deadbolt and the control part to move the latch bolt and the deadbolt in their retracted position and the control part in its first position when the bit is turned in a first direction, and to move the deadbolt in its extended position and the control part in its second position when the bit is turned in a second direction

<Desc / Clms Page number 2>

 opposite to the first direction, said transmission mechanism comprising a gear train of which an output pinion is engaged with a rack carried by the control part.

 A lock with multiple bolts of this type is described, for example, in document EP 0 091 517. Known locks of this type have the advantage of allowing retraction of the half-turn bolt in its retracted position either by means of the nut, acting on the door handle, either by means of the cylinder of the lock cylinder using the key. In the case of an entrance door, a French window or the like, it is thus possible to dispense with providing a door handle on the outside of the door. In addition, the transmission mechanism with gear train exhibits great smoothness and flexibility of operation both during a locking operation and during an unlocking operation of the lock.

 However, this type of lock has the disadvantage of being sensitive to break-ins. Indeed, during a break-in, for example after extracting the lock cylinder, it suffices that the burglar forces one of the bolts up or down in a direction corresponding to the unlocking to cause, via the rod of corresponding control and transmission mechanism, retraction of all bolts, including the latch bolt, in their retracted or unlocked position, thus allowing the door to be opened. This clearly represents a safety disadvantage.

 In addition, in the case where the transmission mechanism includes a tilting arm which acts on the follower arm to cause the retraction of the latch bolt when the barrel of the lock cylinder is turned by means of the key the direction of opening of the lock, an additional angle of rotation beyond the position corresponding to the retracted or unlocked state of the deadbolt and the high and low bolts, it is then necessary to overcome not only the force of return of the spring associated with the latch bolt, but also the return force of another spring, which is usually associated with the follower to return it to its rest position and which generally has a greater force than that of the spring associated with the turn around.

<Desc / Clms Page number 3>

Under these conditions, the user must therefore make a greater effort on the key to rotate the barrel, which can be felt as a nuisance by a user.

 Finally, it is known that the head of the latch bolt of a lock usually comprises, on one of its two vertical lateral faces, a bevel which, at the end of the closing movement of the door leaf, cooperates with a fixed strike on a vertical upright of the door sash to automatically cause the latch bolt to be erased. This bevel must be located on one or the other of the two vertical lateral faces of the latch bolt depending on the direction of closing of the door, to the right or to the left. It is therefore desirable that a user or installer can, if necessary, turn the latch bolt, by rotating it 1800 around its longitudinal axis, without having to disassemble the lock to perform this turning operation. This is not possible with the lock described in the document EP 0 091 517 mentioned above.

 This operation of turning the latch bolt, without removing the lock, is possible with the locks described in documents CH-687 406 and DE-1 226 452. However, the means provided for turning the latch in the locks described in these two documents are relatively complex or occupy a relatively large volume and a location in the lock housing, which, if they are not really annoying in the locks described in these two documents, can be incompatible or annoying , in other models of lock, to accommodate other mechanisms in the housing of the lock, such as for example mechanisms for actuating additional bolts up and down.

 The present invention therefore, firstly, aims to provide a lock with multiple bolts having greater security against an attempted break-in of the kind described above.

 The present invention also aims, secondly, to provide a multiple bolt lock in which the retraction of the latch bolt by means of a key and the cylinder barrel of the lock can be obtained without having to exercise a significant effort on the key.

<Desc / Clms Page number 4>

 The invention also aims, thirdly, to provide a lock with multiple bolts or a lock comprising no dead bolt (only a latch bolt), in which the means making it possible to effect the turning of the half bolt are extremely simple and occupy practically no additional space or volume in the lock housing, so that the lock housing can easily accommodate other mechanisms, for example in the case of a multiple bolt lock .

 According to the present invention, the first above-mentioned object is achieved by the fact that the output pinion and the rack have teeth which are shaped to define an irreversible gear allowing transmission of movement from the output pinion to the rack in both direction of rotation of the output pinion, and preventing transmission of movement from the rack to the output pinion when the control part is in its second position.

 Under these conditions, when the control part is in its second position, that is to say in a position corresponding to the locking position of the additional bolt (s) up and down and also to the locking position of the deadbolt, a burglar who would try to force one or other of the additional bolts up and down towards its unlocking position, will not be able to cause either the retraction of the forced bolt, nor the retraction of the other bolts because , in this case, as will be seen in detail below, the control part is blocked and cannot rotate the output pinion of the transmission mechanism.

 In one embodiment of the present invention, the rack has teeth that are irregular in width and spacing, one of the teeth of the rack having a head having, on one side, a first bevel which, in the second position of the workpiece control, extends tangentially to the head circle of the output pinion and which is in contact with the top of one of the teeth of the output pinion so as to cause a blockage of said control part if the latter is subjected, during 'an attempted break-in, to a force tending to move the control piece from its second position to its first position.

<Desc / Clms Page number 5>

 Preferably, the top of the teeth of the output pinion has a profile in an arc corresponding to the head circle of the output pinion, and the first bevel has a profile in an arc whose radius corresponds to the radius of the head circle of the output pinion and which follows the profile of the top of one of the teeth of said output pinion when the control part is in its second position.

second biseau épouse le sommet profilé en arc de cercle d'une première dent du pignon de sortie, tandis que le sommet profilé en arc de cercle d'une seconde dent du pignon de sortie, consécutive à la première dent, épouse une surface courbe qui est formée sur la crémaillère et qui a un profil en arc de cercle ayant le même centre que l'arc de cercle du profil en arc de cercle du second biseau. Preferably, one of the teeth of the rack has a head having, on one side, a second bevel having an arcuate profile of radius corresponding to the radius of the head circle of the output pinion, and, in the first position of the control room, the

second bevel follows the arcuate profile apex of a first tooth of the output pinion, while the arcuate profile apex of a second tooth of the output pinion, consecutive to the first tooth, espouses a curved surface which is formed on the rack and which has an arcuate profile having the same center as the arc of the arcuate profile of the second bevel.

 In one embodiment of the invention, more particularly intended for a lock comprising two control parts each carrying a rack engaged with the output pinion of the transmission mechanism and each connected to a control rod, respectively upper or lower, carrying respectively at least one additional bolt up or down, the output pinion comprises four teeth which are spaced approximately 90 to the circumference of the output pinion and diametrically opposite two by two, the teeth of a first pair of diametrically opposed teeth having a width of a first value, while the teeth of a second pair of diametrically opposite teeth have a width of a second value, smaller than the first value, and the output pinion has an interdental interval having a third value.

 Preferably, the rack successively comprises, from its furthest end towards its end closest to the control rod, a first tooth whose width has a value smaller than the third value, a second tooth whose width has a value corresponding to said third value, and a third tooth whose width has a value smaller than said third value and whose base is connected to said curved surface, the first and

<Desc / Clms Page number 6>

 second bevels being formed on opposite sides of the head of the second tooth, the interval between the first and second teeth having a value corresponding to the first value and the interval between the second and third teeth having a value corresponding to the second value.

 Preferably, in the second position of the control part, the first bevel of the second tooth of the rack is in contact with the top of a tooth of the output pinion whose width has the first value.

 Preferably, in the first position of the control part, the curved surface of the rack is in contact with the top of a tooth of the output pinion whose width has the first value, and an interval is provided between mutually flanks opposite said tooth of the output pinion and the third tooth of the rack, so that the output pinion can perform a limited additional rotation in a direction corresponding to a reduction in said interval, without causing a displacement of the rack and associated control piece beyond its first position.

 To allow retraction of the latch bolt by means of the key, the transmission mechanism further comprises a rocking arm, which can rock around an axis parallel or coincident with the axis of rotation of the output pinion, and the output pinion carries a drive pin which engages the tilting arm when the output pinion reaches a first position of rotation corresponding to the first position of the control part, for tilting the tilting arm when the output pinion performs said limited additional rotation, said tilting arm being able to act, during its tilting movement, on the follower arm or on the tail of the latch bolt to move the latter in its retracted position.

 Preferably, the output pinion has a cylindrical part which carries said drive lug. The tilting arm has, at one of its ends, a hub part which is mounted on the cylindrical part of the output pinion and which has an arcuate groove which extends over less than 3600 around the part

<Desc / Clms Page number 7>

 cylindrical output pinion and in which is engaged said drive pin. Said drive pin is positioned on the cylindrical part of the output pinion so that it comes into contact with a first end of the arcuate groove to drive the rocking arm when the output pinion reaches its rotational position corresponding to the first position of the control part. The arcuate groove has, in the circumferential direction, from its first end towards its second end, an extent such that the drive pin can move freely in said arcuate groove, without driving the rocking arm, when the output pinion rotates from its first position of rotation at least to a second position of rotation corresponding to the second position of the control part.

 The third object of the invention is achieved by the fact that the follower and the follower arm are constituted by separate parts which are joined to one another and can rotate around a common axis of rotation, and a the disengageable coupling is arranged between the follower and the follower arm, so that in the engaged state of the coupling the follower and the follower arm can rotate together, while in the disengaged state of the coupling, the follower arm can rotate alone around the common axis of rotation.

 Preferably, the follower comprises, in a known manner, on at least one side, a pin used for the rotary mounting of the follower in the housing. In this case, the follower arm is rotatably mounted on the journal, between the follower and a wall of the housing, and the disengageable coupling consists of a coupling finger which is slidably mounted in a blind hole in the follower, the l the axis is parallel to the axis of rotation of the follower and which is open in the direction of the follower arm, said coupling finger being biased by a spring, housed in the blind hole, towards the follower arm and having an end which is engaged in an opening of said follower arm in the engaged state of the coupling.

 Preferably, the end of the coupling finger which is engaged in the opening of the follower arm, is accessible from the outside of the housing through a lumen formed in said wall of the housing, so that the finger coupling can be pushed back into the blind hole, against the force of the spring, using a

<Desc / Clms Page number 8>

 tool inserted in the light, to put the coupling in a disengaged state.

 In the case where the tilting arm of the transmission mechanism is arranged to act on the follower arm, the second object of the invention is achieved by the fact that the opening of the follower arm has the form of an arcuate slot according to a circular arc centered on the axis of rotation of the follower and having an extent such that, during the tilting movement of the rocking arm, the follower arm rotates on the journal of the follower without acting on the coupling finger, therefore without rotate the follower.

 Other characteristics and advantages of the invention will appear better during the following description of an embodiment of the invention given by way of example with reference to the accompanying drawings in which: - Figure 1 is a view of assembly of the lock according to the invention, the cover or lock of the lock housing having been removed to show the internal mechanism of the lock, said mechanism being shown in a state corresponding to the rest position or the extended position of the half bolt -turn and in the retracted position of the deadbolt; - Figure 2 is a partial view corresponding to Figure 1, and in which some elements of the internal mechanism have been removed or shown in thin lines, while other elements of the internal mechanism have been shown in bold to better show some details; - Figure 3 is a partial view corresponding to Figure 2, showing other details; - Figure 4 is an exploded view corresponding to Figure 3, some elements having been removed; - Figure 5 is an exploded side view of an intermediate gear of a gear train forming part of the mechanism of the lock; - Figure 6 is a side view of the gear train output gear; - Figure 7 is a side view of a rocking arm forming part of the lock mechanism;

<Desc / Clms Page number 9>

 - Figure 8 is a view similar to Figure 2, and wherein the elements of the lock mechanism are shown in a state corresponding to the extended position of the deadbolt; - Figure 9 is a partial view corresponding to Figure 8, after removal of certain elements to better show certain details; - Figure 10 shows, on an enlarged scale, a detail of Figure 9; - Figure 11 is a partial view corresponding to Figure 3, some elements of the mechanism having been removed for clarity; - Figure 12 is a partial view of the gear train of the lock mechanism, in which the output gear of the gear train occupies a position corresponding to that of Figure 11, and further showing an associated tilting lever to the output gear wheel; - Figure 13 is a partial view similar to Figure 11, in which the output gear wheel has rotated at a small angle relative to its position shown in Figure 11; - Figure 14 is a view of the lock mechanism in a state corresponding to the position of the output toothed wheel shown in Figure 13, and showing the action of the rocking lever on the follower arm to retract the half bolt turn the lock in its retracted position; - Figure 15 is a partial schematic view showing the latch bolt and the follower in their rest position; - Figure 16 is a sectional view along the line XVIXVI of Figure 15; - Figure 17 is a view similar to Figure 15 showing the latch bolt in its retracted position under the action of the follower of the lock; - Figure 18 is a view similar to Figure 15 showing the latch bolt in an extended position allowing its reversal;

<Desc / Clms Page number 10>

 - Figure 19 is an exploded perspective view showing the latch bolt and the nut in two parts, as well as the coupling means of the two parts of the nut; - Figure 20 is a perspective view showing the latch bolt and the two parts of the follower in the assembled and coupled state; FIGS. 21 to 24 are perspective views similar to FIG. 20, illustrating successive phases of the turning-over operation of the latch bolt.

 Referring to Figure 1, we can see a multiple bolt lock comprising a housing 1 intended to be embedded in a mortise dug in the edge of a door leaf. The housing 1 comprises, in a conventional manner, a plaster 2 (not shown in FIG. 1 but partially shown in FIG. 16), which forms one of the two large vertical faces of the housing 1, a headrest 3, which is integral with the plaster 2 or rigidly fixed thereto, and which, in service, is fixed by screws (not shown) in a shallow notch or groove formed in the edge of the door leaf, and a cover or block 4 under the form of a plate, which extends parallel to the plaster 2 and is detachably attached thereto.

 The lock further comprises, inside the housing 1, a latch bolt 5, a follower 6, which is intended to be actuated by a door handle (not shown), for example of the button type or of the crutch type , for manual actuation of the U-bolt 5, a dead bolt 7, at least one control part, for example two control parts 8 and 9 which, in service, are connected respectively to an upper control rod and to a lower control rod (not shown) respectively carrying at least one top deadbolt and at least one bottom deadbolt (not shown), a lock cylinder 11 comprising a barrel provided with a bit 1 la (not shown in Figure 1, but visible in Figures 3,9, 12 and 14) and adapted to be actuated by means of an appropriate key, and a transmission mechanism 12 which is in drive relationship on the one hand with the bit lla and, on the other hand, with the half-bolt or 5, the deadbolt 7 and the two control parts 8 and 9 to allow the

<Desc / Clms Page number 11>

 operation of elements S, 7, 8 and 9 using said key in a manner which will be described in detail below.

 The U-bolt 5 conventionally comprises a head 5a and a tail Sb. The head Sa, of prismatic shape, passes through an opening 13, of substantially rectangular shape, which is formed in the headrest 3 and in which the head Sa is guided and movable in horizontal translation. The head Sa comprises a vertical lateral face 14 (see also FIGS. 19 to 24) which is situated in a plane parallel to the plaster panel 2, and an opposite vertical lateral face 15 which is bevelled. Two grooves 16 and 17, for example of semi-circular section, are cut respectively in the upper and lower horizontal faces of the head Sa. The grooves 16 and 17 cooperate with projections (not shown) of semi-circular shape corresponding to the section of said grooves, which are formed respectively on the upper edge and on the lower edge of the opening 13, for guiding the head 5a in said opening.

 The tail 5b of the U-bolt 5 is constituted by a cylindrical rod 18, one of the ends of which is rigidly fixed to the head 5a and which is slidably mounted in a bearing 19 formed by an appendage of the plaster 2. The other end of the rod 18 carries a drive piece 21 which is rigidly fixed to said rod. The piece 21 has the shape of a square or a rectangle, the horizontal sides of which have a dimension corresponding to the spacing between the plaster 2 and the wall 4 (see FIG. 16). The part 21 has two projections 22 and 23, which are formed respectively on its vertical sides and which are engaged respectively in horizontal slots 24 and 25 formed respectively in the plaster 2 and in the wall 4. The projections 22 and 23 cooperate with the slots 24 and 25 to provide additional guidance in horizontal translation of the latch bolt 5. At their end closest to the head Sa, the slots 24 and 25 open into vertical slots 26 (FIG. 1) formed respectively in the plaster 2 and in the funnel 4. The slots 26 allow the U-bolt 5 to be turned over by a rotation of 180 thereof around the longitudinal axis 20 of the tail 5b in a manner which will be described in detail below. .

<Desc / Clms Page number 12>

 A spring 27 is provided in the housing 1 to urge the latch 5 in a rest position in which the head 5a projects partially outside the housing 1, through the opening 13 thereof, as shown in FIG. 1. The spring 27 may for example be constituted by a torsion spring, which is placed around a stud 28 secured to the plaster 2 and which comprises a first branch 27a bearing against a stop 29 of the plaster 2 and a second branch 27b bearing against the rear vertical face 31 of the head 5a of the U-bolt 5.

 The follower 6, the structure of which will be described in detail below, is mounted in the housing 1 so as to be able to rotate about an axis of rotation 32, and it comprises a follower arm 33 capable of acting on the workpiece. drive 21 of the tail 5b of the U-bolt 5 to bring the head 5a of the latter into a retracted position inside the housing 1 in a manner which will be described in detail below. On the side opposite to the headrest 3, the follower 6 has a toothed sector 34, the teeth of which are engaged with the teeth of a rack 35 which is guided and movable in vertical translation in the housing 1. A helical spring 36, which has a greater restoring force than that of the spring 27, is arranged around a non-toothed part of the rack 35 and bears, at its lower end, against a shoulder 37 of the plaster 2 and, at its upper end, against a stop 38 fixed to the upper end of the rack 35.

 On the side opposite to the follower arm 33, the follower 6 has a projection 39 which, in the rest position of the follower 6, which also corresponds to the rest position or extended position of the latch bolt 5, is supported on a stop 41 formed on the plaster 2. Starting from its rest position, the follower 6 can be turned clockwise (seen in Figure 1) around its axis of rotation 32 by means of a drive rod 42 of non-circular section , for example with a square section, at least one of the two ends of which is connected to a door handle. Thus, in service, when a user acts on the door handle so as to rotate the follower 6 clockwise, the follower arm 33 acts on the drive piece 21 of the tail 5b of the latch bolt 5 to move the latter to the right (seen in FIG. 1) and, consequently, return the head 5a of the latch bolt in the

<Desc / Clms Page number 13>

 housing 1. Another stop 43 can be formed on the plaster 2 to limit, in cooperation with the projection 39 of the follower 6, the angular movement of said follower in the clockwise direction and, consequently, also to limit the movement of retraction of the bolt U-turn 5 inside the housing 1, for example when the front edge 44 of the head 5a of the U-bolt reaches flush with the outer face 3a of the headrest 3. During the rotation of the follower 6 in the direction hourly, the toothed sector 34 of said follower acts on the rack 35 to move it vertically downwards, so that the stop 38 of the rack compresses the spring 36.

When the user releases the door handle, the spring 36 expands and pushes the stop 38, so that the rack 35 is moved vertically upward and in turn acts on the toothed sector 34 of the follower 6 to rotate it counterclockwise, in order to return it to its rest position defined by the projection 39 and the stop 41. Simultaneously, the latch bolt is returned to its extended position by the branch 27b of the spring 27.

The deadbolt 7 comprises, conventionally, a head 7a and a tail 7b (better visible in FIG. 8) which is in one piece with the head 7a. The head 7a has the shape of a rectangular parallelepiped and can slide horizontally in a rectangular opening 45 formed in the headrest 3. The tail 7b has a groove 46 which is formed and extends horizontally in a flat vertical lateral face 47 of the tail which is parallel and faces the plaster 2. The internal face of the plaster 2 carries a horizontal rib (not shown) which is engaged in the groove 46 of the tail 7b and cooperates with said groove to guide the deadbolt 7 in horizontal translation . In the upper part of the tail 7b, on its vertical lateral face opposite to the face 47, the tail 7b comprises several teeth, for example four teeth 48 each having a profile substantially in the form of dz
The transmission mechanism 12 essentially comprises a gear train 49 and a rocking arm 51.

 As shown in FIGS. 1 and 2, the gear train 49 comprises a first toothed wheel or input wheel 52 constituted by an external gear ring, which is mounted in a cylindrical housing 53 of the plaster 2 so as to be able to

<Desc / Clms Page number 14>

tourner autour d'un axe virtuel de rotation 54 qui est légèrement décalé vers le haut par rapport à l'axe virtuel de rotation 55 du barillet du cylindre de serrure 11. La couronne dentée 52 comporte une fente radiale 56 dans laquelle est engagé le panneton lla du cylindre de serrure 11 comme montré dans les figures 3,9, 12 et 14. Ainsi, lorsque le barillet du cylindre de serrure 11 est tourné dans le sens horaire ou anti-horaire au moyen d'une clef appropriée, le panneton lla fait tourner dans un sens correspondant la couronne dentée 52 autour de l'axe 54. La couronne dentée 52 est en prise avec une paire de secondes roues dentées 57a et 57b qui peuvent tourner respectivement sur des plots cylindriques 58 et 59 solidaires du palâtre 2.

rotate around a virtual axis of rotation 54 which is slightly offset upwards relative to the virtual axis of rotation 55 of the cylinder of the lock cylinder 11. The toothed crown 52 has a radial slot 56 in which the bit is engaged lla of the lock cylinder 11 as shown in Figures 3,9, 12 and 14. Thus, when the barrel of the lock cylinder 11 is turned clockwise or counterclockwise by means of an appropriate key, the bit lla rotates the toothed crown 52 in a corresponding direction around the axis 54. The toothed crown 52 is engaged with a pair of second toothed wheels 57a and 57b which can rotate respectively on cylindrical pads 58 and 59 integral with the plaster 2.

 The gear train 49 further comprises a third toothed wheel 61 which can rotate on a cylindrical stud 62 integral with the plaster 2 and which carries two coaxial teeth 63 and 64 which have pitch circles of different diameters and different numbers of teeth. The toothing 63 which has the greatest number of teeth is engaged with the two toothed wheels 57a and 57b.

 The gear train 49 further comprises a fourth toothed wheel 66, with multiple teeth, which can rotate around a cylindrical stud 67 secured to the plaster 2. As shown in FIG. 5, the toothed wheel 66 is in fact composed of two separate parts 68 and 69. The part 68 is constituted by a toothed wheel which has a toothing 71 on its periphery and two drive pins 72 and 73 which are arranged in diametrically opposite positions on one side of the toothed wheel 71. On the side opposite to the lugs 72 and 73, the toothed wheel 71 comprises a cylindrical hub 74 which is rotatably mounted on the cylindrical stud 67 and which has on its outer peripheral surface at least one flat, preferably two flat. The part 69 is constituted by a flat disc which has in its middle an oblong opening 75 whose contour corresponds to the external contour of the hub 74 of the part 68. Thus, when the two parts 68 and 69 are assembled, by engagement of the hub 74 in opening 75, they can rotate together. The disc forming the part 69 has a toothing 76 which has a larger pitch circle than that of the toothing 71 and a greater number of teeth. Tooth 76 is

<Desc / Clms Page number 15>

 engaged with the toothing 64 of the toothed wheel 61, while at least one of the two drive pins 72 and 73 is engaged with one of the teeth 48 of the tail 7b of the deadbolt 7.

 Finally, the gear train 49 comprises a fifth toothed wheel 77 with two teeth, which can rotate on a cylindrical stud 78 integral with the plaster 2. As is more particularly visible in FIGS. 4 and 6, the toothed wheel 77 successively comprises , in the axial direction, a first part 79 substantially in the form of a disc, carrying a toothing 81, a second cylindrical part 82, which has a smaller diameter than that of the part 79 and which carries a drive pin 83, and a third part 84, which has an even smaller diameter than that of part 82 and which carries, in the embodiment described here, four teeth, namely a first pair of diametrically opposite teeth 85, and a second pair of teeth 86, diametrically opposite and spaced about 900 from the teeth 85. The toothing 81 is in engagement with the toothing 71 of the toothed wheel 66. Since, as will be seen later, the toothed wheel 77 performs e n service a rotation which is at most a little more than half a turn, the part 79 of the toothed wheel 77 does not need to be toothed over its entire circumference. The toothing 81 can therefore extend over an arc corresponding to an angle of about 2700 k as shown in FIG. 4. The part 84, with its four teeth 85 and 86, constitutes the output pinion of the gear train 49.

 The output pinion 84 is engaged with two racks 87 and 88 which are disposed respectively on either side of the output pinion 84 and which respectively form an integral part of the control part 8 and of the control part 9, as this is particularly visible in Figures 3 and 4. The two control parts 8 and 9 are guided so as to be movable in vertical translation, by guide means which are provided conventionally in the housing 1 of the lock and which will not be described in detail since their description is not necessary for the understanding of the present invention.

 The numbers of teeth of the gear wheels of the gear train 49 are chosen so as to have ratios of

<Desc / Clms Page number 16>

 transmission such that when the ring gear 52 makes about two turns, the gear 66 makes about one turn and the gear 77 makes about half a turn. It goes without saying, however, that other transmission ratios could be chosen, for example in such a way that when the toothed crown 52 performs approximately one revolution, the toothed wheel 66 performs approximately one revolution and the toothed wheel 77 performs approximately one half tower.

 In the lock according to the invention, the output pinion 84 of the gear train 49 and the two racks 87 and 88 have teeth which are shaped to define an irreversible gear. More precisely, the output pinion 84 can transmit a movement to the two racks 87 and 88 in the two directions of rotation of the output pinion 84, but neither of the two racks can transmit a movement to the output pinion in particular when the latter and the two racks are in a position corresponding to the locking position of the deadbolts of the lock, as will be explained in detail below.

 Each of the two racks 87 and 88 has teeth that are irregular in width and in spacing, as is more particularly visible in FIG. 4. More precisely, each of the two racks 87 and 88 successively comprises, from its most distant end towards its end closest to the end 8a or 9a of the corresponding control part 8 or 9, to which one of the two aforementioned control rods is connected, a first tooth 89 whose width has a value a smaller than the value b of the interval between two successive teeth 85 and 86 of the output pinion 84, a second tooth 91, the width of which has a value c corresponding to the aforementioned value b, and a third tooth 92, the width of which has a value d more smaller than the aforementioned b value.

 The teeth 85 and 86 of the output pinion 84 preferably have different widths. For example, as shown, the two teeth 85 have a width whose value e is greater than the value f of the width of the teeth 86. Under these conditions, the interval 93 between the teeth 89 and 91 of each of the two racks 87 and 88 has a value corresponding to the value e of the width of the teeth 85, while the interval 94 between the teeth 91 and 92 of each of the two racks

<Desc / Clms Page number 17>

 has a value corresponding to the value f of the width of the teeth 86 of the output pinion 84.

 As shown in FIG. 4, two bevels 95 and 96 are formed respectively on opposite sides of the head of the second tooth 91 of each of the two racks 87 and 88. The top of the two teeth 86 of the output pinion 84 has a profile in an arc corresponding to the head circle of the output pinion 84, said head circle having for example a diameter equal to the diameter of the cylindrical part 82 of the toothed wheel 77.

 The top of the teeth 85 of the output pinion 84 also has an arcuate profile corresponding to the head circle of the output pinion 84, but having however a radius very slightly smaller than that of the head circle. Preferably, the bevel 95 of the tooth 91 of each of the two racks 87 and 88 has a circular arc profile whose radius corresponds to the radius of the head circle of the output pinion 84 or, more precisely, to the radius of the circle on which is the top of the teeth 85 of said output pinion. Likewise, the bevel 96 of tooth 91 of each of the two racks 87 and 88 has a profile in an arc of a circle whose radius is equal to the radius of the head circle of the output pinion 84.

 A curved surface 97 is formed on each of the two racks 87 and 88, following the tooth 92 thereof, and is connected to the foot of this tooth 92. The curved surface 97 of each rack has an arcuate profile of circle which has the same center as the arc of the circular arc profile of the bevel 96, and which has a radius of curvature equal to the radius of the circle on which is the top of the teeth 85 of the output pinion 84. Otherwise said, when the two control parts 8 and 9 and the toothed wheel 77 are in the position shown in Figure 3, which corresponds to the retracted position or unlocking position of the deadbolts of the lock, the profiles in an arc bevels 96 of the teeth 91 and the arcuate profiles of the curved surfaces 97 of the two racks 87 and 88 are located respectively on concentric circles, centered on the axis of rotation of the output pinion 84, and the top of the teeth 85 respectively marries the s curved urfaces 97 of the two racks, while

<Desc / Clms Page number 18>

 that the top of the teeth 86 respectively matches the bevels 96 of the teeth 91 of the two racks.

 In addition, when the toothed wheel 77 is in the position shown in FIG. 3, a gap 98 is formed between the flanks mutually opposite each tooth 85 of the output pinion 84 and the tooth 92 of the rack. 87 or 88. The values e and f of the width of the teeth 85 and 86 of the output pinion 84, therefore the value b of the interdental interval, and the value d of the width of the tooth 92 of each of the two racks 87 and 88 are chosen such that each of the two intervals 98 has a sufficient width for the output pinion 84 to be able, from the position shown in FIG. 3, to make an additional rotation limited in a clockwise direction, that is that is to say in the direction corresponding to a reduction in the interval 98, without causing a displacement of the racks 87 and 88 and of the associated control parts 8 and 9 beyond their position corresponding to the unlocking position of the deadbolts .

 As is better visible in FIG. 7, the rocking arm 51 of the transmission mechanism 12 comprises, at one of its ends, a hub part 101 which is mounted on the cylindrical part 82 of the toothed wheel 77 as shown in particular in FIGS. 12 and 14. The hub part 101 comprises, in its lateral face which faces towards the part 79 of the toothed wheel 77, an arcuate groove 102 which extends over less than 360 around the cylindrical part 82 of the toothed wheel 77 and in which the drive lug 83 of the toothed wheel 77 is engaged. Thus, the drive lug 83 can move freely in the groove 102 without driving the rocking arm 51 during part of the rotational movement of the toothed wheel 77 as will be described in detail below. At its end opposite to the hub part 101, the tilting arm 51 is preferably provided with a roller 103 which can rotate freely on an axis 104 carried by the tilting arm and which is able to act on the follower arm 33 when the arm 51 swings clockwise under circumstances which will be described in detail below.

 Referring now to Figures 15, 16, 19 and 20, it can be seen that the follower 6 and the follower arm 33 of the lock according to

<Desc / Clms Page number 19>

 the invention are constituted by separate parts 105 and 106, respectively, which are joined to one another and can rotate around a common axis of rotation 32. A disengageable coupling 107 is arranged between the two parts 105 and 106, so that in the engaged state of the coupling, the two parts 105 and 106 can rotate together, while in the disengaged state of the coupling, the follower arm 33 can rotate alone around the common axis of rotation 32.

 The toothed sector 34 and the projection 39 which have been described above are formed on the part 105 constituting the follower 6. This part 105 comprises, on at least one side, preferably on its two sides, pins 108 and 109 which are coaxial and which are respectively housed in circular openings 111 and 112 formed respectively in the plaster 2 and in the wall 4 for the rotary mounting of the follower 6 in the housing 1 of the lock. The part 106 forming the follower arm 33 is rotatably mounted on the pin 109, between the follower 6 and the bolt 4, as shown in FIG. 16.

Naturally, in an alternative embodiment of the invention, the part 106 forming the follower arm 33 could be rotatably mounted on the pin 108, between the follower 6 and the plaster 2.

 The disengageable coupling 107 is here constituted by a coupling finger 113 which is slidably mounted in a blind hole 114 of the part 105 (Figures 16 and 19), whose axis is parallel to the axis of rotation 32 of the follower 6 and which is open in the direction of the part 106. The coupling finger 113 is biased by a spring 115, housed in the blind hole 114, towards the part 106, so that, in the engaged state of the coupling 107, an end part 113a of the coupling finger 113 is engaged in an opening 116 of the part 106. Preferably, the end part 113a of the coupling finger 113 has a smaller diameter than the remaining part of the coupling finger and an axial length substantially equal to the thickness of the part 106. Thus, an annular shoulder is formed between the end part 113a and the remaining part of the coupling finger. In the assembled state of the two parts 105 and 106, the annular shoulder of the coupling finger 113 is pressed against the edge of the opening 116 of the part 106 by the spring 115, so

<Desc / Clms Page number 20>

 that the coupling finger 113 cannot escape through the opening 116.

 The end 113a of the coupling finger 113 is accessible from outside the housing 1 of the lock through a hole 117 (FIG. 16) formed in the recess 4 of the housing 1. Thus, the coupling finger 113 can be pushed inward from the blind hole 114, against the force of the spring 115, using an appropriate tool inserted into the hole 117, to put the coupling 107 in a disengaged state then allowing the half-bolt to be turned over turn 5 as will be described in detail later. The light 117 preferably has the form of a slot which has a width slightly smaller than the diameter of the end portion 113a of the coupling finger 113 and which is arched in an arc centered on the axis of rotation 32 of the follower 6.

 In the case where the tilting arm 51 is arranged to act on the follower arm 33, the opening 116 of the part 106 forming the follower arm 33 preferably has the form of a slot arcuate in an arc of circle centered on the axis of rotation 32 of the follower 6. In this case, the slot 116 has an extent such that, during the rocking movement of the rocking arm 51, the follower arm 33 rotates clockwise on the pin 109 of the follower 6 without acting on the coupling finger 113, therefore without turning the follower 6.

 We will now describe the operation of the lock according to the invention. Starting from the state represented in FIGS. 2 and 3, in which the gear wheels of the gear train 49 and the two control parts 8 and 9 are in a position corresponding to the retracted state or unlocking state of the bolts frames of the lock, when a user inserts an appropriate key into the barrel of the lock cylinder 11 and rotates the latter anti-clockwise, the bit 11a of the lock cylinder turns the ring gear 52 in the direction counterclockwise. This has the effect of rotating the toothed wheel 66 clockwise and the toothed wheel 77 counterclockwise. As a result, the drive lugs 72 and 73 of the toothed wheel 66 act on the teeth 48 of the tail 7b of the deadbolt 7 to cause the head 7a of the latter to come out of the housing 1, while the teeth 85 and 86 of the output pinion 84 of the toothed wheel

<Desc / Clms Page number 21>

 77 act on the teeth 92 and 91 of the two racks 87 and 88 to move the control piece 8 vertically upwards and the control piece 9 vertically downwards.

 It will be noted that, during the rotation of the toothed wheel 77 anticlockwise, the drive pin 83 moves freely in the arcuate groove 102 of the hub 101 of the rocking arm 51, from the end 102a towards the end 102b of said arcuate groove, without driving the rocking arm 51.

 After the bit 11a and the crown gear 52 have made a little less than two turns, the gear wheel 66 has made at the same time about one turn and the gear wheel 77 has made a half turn, as shown in FIGS. 8 and 9. The deadbolt 7 is then in its fully extended position and the two control parts 8 and 9 are in their position corresponding to the locking position of the additional deadbolts up and down. In this situation, the top of each of the two teeth 85 (those which have the greatest width) of the output pinion 84 is in contact with the bevel 95 of the tooth 91 of each of the racks 87 and 88, respectively, and the profile in an arc of the apex of each tooth 85 follows the arcuate profile of the bevel 95 of the corresponding tooth 91 of the rack 87 or 88, as is better visible in FIG. 10. It will be noted that in this position, the output pinion 84 can still perform a limited rotation clockwise without its teeth 85 and 86 driving the racks 87 and 88.

This makes it possible to bring the bit 1a of the lock cylinder 11 back to the six o'clock position so that the key can be extracted from the lock cylinder 11, without moving the control parts 8 and 9, therefore keeping the deadbolts in their locking position.

 It will also be noted that, when the deadbolts of the lock are in their locked position, if, during an attempted break-in, a burglar succeeds in gaining access to one of the additional deadbolts up or down of the lock and tries to force this bolt towards its unlocking position, a blocking of the corresponding control part 8 or 9 occurs. This will now be explained with reference to Figure 10. Suppose, for example, that

<Desc / Clms Page number 22>

 during a burglary attempt, the burglar subjects the deadbolt high a force directed vertically downward to force this bolt towards its unlocked position. Under these conditions, the control part 8 will be subjected to a force FI directed vertically downwards and the bevel 95 of the tooth 91 of the rack 87 will then apply to the top of the tooth 85 of the output pinion 84 a force F2 which is directed radially towards the axis of rotation of said output pinion, as shown in FIG. 10. Consequently, the tooth 85 of the output pinion will exert on the bevel 95 of the tooth 91 of the rack 87 a reaction force F3 of equal value and opposite direction to the force F2. This force F3 is broken down into a horizontal component F3h and a vertical component F3v. Since the control part 8 is guided in vertical translation by guide means shown diagrammatically in FIG. 10 by a support 118, the latter exerts on the rack 87 a reaction force F4 which counterbalances the horizontal component F3h, while the component F3v opposes the force FI applied to the control part 8. The latter is therefore blocked and cannot move vertically downwards, so that the rack 87 cannot rotate the output pinion 84 in clockwise and that all the deadbolts of the lock cannot be forced to come into their unlocked position. The same would happen if the burglar tried to force the deadbolt down to its unlocked position. Indeed, in this case, the control part 9 is subjected to a force directed vertically upwards and the other tooth 85 of the output pinion 84 then exerts, in cooperation with the support 119 associated with the control part 9 , a locking action on the tooth 91 of the rack 88, thus preventing the control part 9 from moving vertically upwards.

 We will now describe an operation for unlocking the deadbolts of the lock. To perform this unlocking operation, starting from the situation shown in Figures 8 and 9, the user inserts his key into the barrel of the lock barrel 11 and rotates the barrel, by means of the key, clockwise . As a result, the bit 1 rotates the toothed crown 52 clockwise, which has the effect of rotating the toothed wheel

<Desc / Clms Page number 23>

 66 counterclockwise and gear 77 clockwise. During the rotation of the toothed wheel 66 anti-clockwise, the drive pins 72 and 73 of this wheel cooperate with the teeth 48 of the tail 7b of the deadbolt 7 to retract the latter in its retracted position at inside the housing 1.

 During the rotation of the toothed wheel 77 clockwise, the tops of the teeth 85 of the output pinion 84 slide first of all on the bevels 95 of the teeth 91 of the racks 87 and 88 without entraining the latter. Then, the teeth 85 of the output pinion act on the sides of the teeth 89 of the two racks 87 and 88 to move the control part 8 downwards and the control part 9 upwards. Then, the teeth 86 of the output pinion 84 engage between the teeth 91 and 92 of the racks 87 and 88 and act on the sides of the teeth 91 of the two racks to continue to move the control part 8 downwards and the part 9 up.

 After the toothed wheel 77 and its output pinion 84 have made a U-turn, all the deadbolts of the lock are in their retracted or unlocked position and the tops of the teeth 86 of the output pinion 84 are in contact with the bevels 96 of the teeth 91 of the two racks 87 and 88, while the tops of the teeth 85 of said output pinion are in contact with the curved surfaces 97 of said racks, as shown in FIGS. 2 and 3. Furthermore, in this situation, intervals 98 remain between the sides mutually opposite the teeth 85 of the output pinion 84 and the teeth 92 of the racks 87 and 88.

 It will be noted that, during the rotation of a half-turn effected by the toothed wheel 77 clockwise, the drive pin 83 moves freely clockwise in the arcuate groove 102 of the hub 101 of the rocking arm 51 without training the latter. When the toothed wheel 77 has rotated by half a turn, from the position shown in FIG. 8 to the position shown in FIGS. 2 and 12, the drive lug 83 of the toothed wheel 77 is then in the vicinity from the end 102a of the arcuate groove 102, as shown in FIG. 12.

<Desc / Clms Page number 24>

 As indicated above, the intervals 98 have a dimension such that the toothed wheel 77 and its output pinion 84 can still make an additional rotation limited in a clockwise direction, by an angle of approximately 220 corresponding to the width of the intervals 98. , without driving the racks 87 and 88, as results from a comparison of FIGS. 11 and 13. During this limited additional rotation of the toothed wheel 77 clockwise, the drive lug 83 comes into contact with the end 102a of the arcuate groove 102, which has the effect of rotating the rocking arm 51 clockwise, as indicated by the arrow F in FIG. 14. Consequently, the roller 103 of the rocking arm 51 acts on the follower arm 33 to rotate it clockwise around the axis of rotation 32 of the follower 6. The follower arm 33 then acts on the drive piece 21 of the tail 5b of the latch 5 to retract the head 5a of the latter inside the housing 1 of the lock, as indicated by the arrow G in FIG. 14, while pushing back the branch 27b of the spring 27 which has a relatively weak force.

 Note that during the rotation of the follower arm 33 clockwise, thanks to the presence of the arcuate opening 116 of the follower arm, the latter does not act on the coupling finger 113. It as a result that the follower 6 is not rotated clockwise and that the user does not need to exert excessive force to cause the retraction of the latch bolt 5 in the housing 1, because it does not have to overcome the relatively large force of the spring 36, but only the force of the spring 27.

 Then, when the user releases the key, the spring 27 pushes the head 5a of the latch bolt 5 out of the housing 1. The drive part 21 rotates the follower arm 33 counterclockwise, that is that is to say in the direction opposite to the direction of the arrow F in FIG. 14, so that the follower arm 33 acts on the roller 103 of the tilting arm 51 to rotate the latter also in the counterclockwise direction. The arm 51 is thus returned to the rest position shown in FIG. 12. During this rotational movement of the arm 51, the end 102a of the groove 102 acts on the drive lug 83 and rotates the wheel toothed 77 counterclockwise

<Desc / Clms Page number 25>

 clockwise to the position shown in FIG. 12. During this rotation of the toothed wheel 77 counterclockwise, the tops of the teeth 85 and 86 of the output pinion 84 slide respectively on the curved surfaces 97 and on the bevels 96 of the racks 87 and 88, without moving them, so that all the deadbolts of the lock remain in their unlocked position. The rotation of the toothed wheel 77 counterclockwise under the action of the end 102a of the groove 102 on the drive pin 83 also rotates the toothed crown 52 also in the counterclockwise direction, thus forcing the bit to return to the six o'clock position shown in Figure 12 or to a position close to this position, so that the key can then be removed from the lock barrel 11.

 When the deadbolts of the lock are in their unlocked position, the U-bolt 5 can also be retracted in a conventional manner inside the housing 1 of the lock by acting on the door handle so as to rotate the drive rod 42 with a square section in a clockwise direction (seen in FIGS. 15 and 17). Under these conditions, the drive rod 42 rotates the follower 6 clockwise and the coupling finger 113 acts on the end 116a of the arcuate opening 116 of the follower arm 33 to rotate the latter in the clockwise as indicated by arrow A in Figure 17. As a result, the follower arm 33 acts on the drive piece 21 of the tail 5b of the latch 5 to retract the head 5a of the latter to the inside the housing 1 of the lock, so that the door can be opened by pulling or pushing on the handle depending on whether the door opens inwards or outwards. As soon as the user releases the door handle, the spring 36 returns the follower 6 to its rest position and the spring 27 returns the latch 5 to the position shown in FIG. 15.

 Referring to Figures 16,18 and 20 to 24, we will now describe how the latch bolt 5 can be turned by a rotation of 180 "around the axis 20 of the tail 5b, in the case where the bevel 15 of the head 5a is not on the right side for the door on which the lock is to be installed For this purpose, it suffices to introduce into the arched opening 117 of the plug 4 an appropriate tool, such as a rod

<Desc / Clms Page number 26>

 cylindrical, to push the coupling finger 113 inside the blind hole 114 of the rod 6, as indicated by arrow B in FIG. 16, until the end portion 113a of the coupling finger 113 either completely out of the opening 116 of the follower arm 33 (FIG. 21). At this moment, the branch 27b of the spring 27 pushes the head 5a of the latch 5 in the direction of the arrow C (FIG. 18) and causes the head 5a to come completely out of the housing 1 of the lock through the opening 13 of the headrest 3. At the same time, the drive piece 21 of the tail 5b of the latch bolt causes the follower arm 33 to tilt back, as indicated by the arrow D in FIG. 18, until the moment where the two lugs 22 and 23 of the drive piece 21 abut against the left edge of the vertical slots 26 of the plaster 2 and the plug 4. At this time, by grasping the head 5a of the latch 5 to the hand, it is rotated 1800 around the axis 20 to move it from the position shown in Figure 22 to the position shown in Figure 23. This rotation of the head 5a is possible despite the square shape of the part drive 21 because, at this time, the latter is opposite the two slots 26 formed r respectively in the plaster 2 and in the wall 4. After the head 5a has been turned 180, it then suffices to push it by hand into the opening 13 of the headrest 3, in the opposite direction to that of the arrow C, so as to reengage the projections 22 and 23 of the drive piece 21 in the horizontal slots 25 and 24 of the wall 4 and the plaster 2. At the same time, using the tool still engaged in the light 117 of the plaster 4 and in the opening 116 of the follower arm 33, the latter is tilted in the direction of the arrow E as indicated in FIG. 24, that is to say in the opposite direction to that of the arrow D in FIG. 18, until the coupling finger 113 snaps back into the opening 116 of the follower arm 33 under the action of the spring 115. At this moment, the follower arm 33 and the follower 6 are again coupled to each other as shown in Figure 24, and the tool can be removed from the light 117 of the land 4.

 It goes without saying that the embodiment of the invention which has been described above has been given by way of purely indicative and in no way limitative example, and that numerous modifications can be easily made by those skilled in the art. without leaving the

<Desc / Clms Page number 27>

 part of the invention. For example, instead of acting on the follower arm 33, the tilting arm 51 could be shaped and arranged to act directly on the drive part 21 or on another drive part linked to the tail 5b of the half bolt - tower 5.

 In addition, although the invention has been described more particularly with regard to a multiple bolt lock in which there are provided two control parts 8 and 9 for actuating respectively the upper and lower control rods associated with the high deadbolts and bottom, the invention is also applicable to a lock comprising a single control part, the two ends of which are respectively connected to the upper control rod and to the lower control rod, these two control rods carrying deadbolts high and bottom, which extend horizontally and protrude permanently onto the edge of the door leaf. In this case, the output pinion 84 may comprise a single tooth 85 and a single tooth 86.

 In addition, the present invention, considered under the aspect of turning the latch 5, is also applicable to a lock comprising no dead bolt, therefore no control part, no lock cylinder and no transmission mechanism. In the latter case and also in the case of a multiple bolt lock in which the rocking arm 51 is arranged to act directly on the drive part 21 or on another part linked to the tail 5b of the U-bolt 5 , it is no longer necessary for the opening 116 of the follower arm 33 to have the shape of an arcuate slot, and this opening 116 may simply have the shape of a circular hole with a diameter corresponding to that of the finger d 113.

Claims (3)

 CLAIMS 1. Door lock, comprising a) a housing (1), b) a latch bolt (5) having a head (usa) and a tail (db), which is guided and movable in horizontal translation in the housing , c) a spring (27) urging the latch bolt into an extended position in which the head of the latch bolt projects partially out of the housing, and d) a follower (6) intended to be actuated by a handle of door and comprising a follower arm (33) capable of acting on the tail of the latch bolt to bring the head of the latter in a retracted position inside the housing when a user acts on the door handle, characterized in that the follower (6) and the follower arm (33) consist of separate parts (105, 106) which are joined to one another and can rotate around a common axis of rotation (32), and a disengageable coupling (107) is arranged between the follower (6) and the follower arm (33), in such a way Note that in the engaged state of the coupling the follower and the follower arm can rotate together, while in the disengaged state of the coupling, the follower arm can rotate alone around the common axis of rotation.  2. Door lock according to claim 1, in which the follower (6) comprises, on at least one side, a pin (109) used for the rotary mounting of the follower in the housing (1), characterized in that the arm of follower (33) is rotatably mounted on the journal (109), between the follower (6) and a wall (4) of the housing, and the disengageable coupling (107) consists of a coupling finger (113) which is slidably mounted in a blind hole (114) of the follower, whose axis is parallel to the axis of rotation (32) of the follower and which is open in the direction of the follower arm (33), said coupling finger being urged by a spring (115), housed in the blind hole (114), towards the follower arm and having one end (113a) which is engaged in an opening (116) of said follower arm in the engaged state of the coupling . <Desc / Clms Page number 29>  3. Door lock according to claim 2, characterized in that the end (113a) of the coupling finger (113) which is engaged in the opening (116) of the follower arm (33), is accessible from the outside of the housing (1) through a lumen (117) formed in said wall (4) of the housing, so that the coupling finger can be pushed back towards the inside of the blind hole (114), against the force of the spring (115), using a tool inserted into the light, to put the coupling (107) in a disengaged state.