FR2775716A1 - DOUBLE BARREL SAFETY CYLINDER - Google Patents

Abstract

Safety cylinder (1) for lock comprising two barrels each consisting of a stator (1a, 1b) and a rotor (2a, 2b), the rotors cooperating with a single rotary bit (7) which is arranged between them and can be driven by a trainer, said trainer being made up of two half-trainers (12a, 12b) each associated with one of the rotors, the half-trainers being capable of relative translation and being resiliently biased towards the relative position which they occupy in the absence of a key, the two half-coaches being free to rotate relative to each other, the coach comprising a single spring (20) consisting of a central portion interposed between the half -coaches to keep them elastically spaced from each other, from two intermediate portions extending on either side of the central portion, each intermediate portion being housed through the associated half-coach to ensure a connection sound between the half-coaches, and two external portions extending from the intermediate portions, each external portion bearing on an axially external face of the associated half-coach, the free end of each external portion being intended to cooperate with a key tip for moving the driver in axial translation, the external portions of the spring having a stiffness greater than that of the central portion.

Description

DOUBLE BARREL RETREAT CYLINDER

  The invention relates to security cylinders intended for controlling a lock, said cylinders comprising two security barrels which allow control of the lock on each side of the door on which said lock is arranged. A double barrel safety cylinder is a well-known device described, for example, in French patent application 2,686,641. This safety cylinder comprises two barrels each consisting of a stator and a rotor capable of pivoting around an axis relative to the stator, each rotor comprising a key housing in which protruding keying means, the two stators being constituted by coaxial cylindrical shells, which are linked together according to a generator by a resistant rectilinear beam to form a stator block. Each rotor has, at its end opposite the key entry, a cylindrical recess, on the side wall of which two diametrically opposite slots have been provided. Each of the two barrels is capable of driving, via a mobile driver, a rotary bit carried by the ends of the two rotors, the bit being axially positioned relative to the stator block by means of mechanical retaining means which are inserted between each of the stators and the bit and which engage in the ends of each of the rotors, so that these retaining means act not only for the axial positioning of the bit with respect to the two stators, but also for the axial retention of each rotor

in its associated stator.

  In known manner, the driver, which allows one of the rotors to be angularly secured to the bit, is a part carried by the ends of the two rotors and capable of axial translation movement relative to the stator block so as to ensure the mechanical clutch between one or the other of the rotors and the bit, depending on the axial position it occupies. The displacement of the driver is carried out under the push of the end of the key when said key is engaged in the key housing of one of the rotors: in this case, the end of the key pushes the driver into a position , o it ensures the clutch between the rotor, o is engaged the key, and the bit; in this position, the other rotor of the stator block is disengaged relative to the bit. Generally, the coach is made up of two parts having the same profile comprising two diametrically opposite lugs, these two parts being linked together by a common axis and being able to pivot freely relative to one another; the bit comprises a cylindrical collar o is formed a median veil, in which an opening has been made, the outline of which corresponds to the common profile of each of the two parts of the coach. When the driver is engaged with the first rotor and with the bit, the first part of the driver has its pins engaged in the hole of the bit and in slots made in the side wall of the end recess of the first rotor ; in this position, the second part of the coach has its lugs engaged in the slots in the end recess of the second rotor and thus remains angularly positioned relative to this

second rotor.

  When the lock is at rest, the angular position of the bit relative to the stator block and the angular positions of the rotors relative to said stator block are perfectly defined; in this relative position, the profiles of each part of the coach are

  vis-à-vis the corresponding holes in the bit wall.

  When a key is engaged in the first rotor, the coach is positioned axially so that the profile of its first part penetrates into the orifice of the blade of the bit, this first part nevertheless remaining mechanically engaged with the first rotor. This position makes it possible to turn the first rotor by means of its associated key by driving the bit and the first part of the coach, while the second part of the coach is not driven in rotation and remains engaged with the second rotor; due to the rotation of the bit, the second part of the coach is then no longer in front of the orifice allowing it to be secured to the veil of the bit and the coach can therefore no longer be maneuvered

  axial translation by the end of the key associated with the second rotor.

  As a result, as soon as a key is inserted into the key housing of the first rotor and the first rotor has turned angularly relative to its rest position which allows the extraction of the key, it is impossible to operate the lock by a key inserted into the key housing of the second rotor, which is still in its rest position: in fact, the key can no longer be fully pressed into its key housing since the second part of the trainer comes into abutment against the veil of the bit. This drawback is particularly serious, if the first rotor has been operated by a sick person inside a room, since it is no longer possible to enter the room in

  manipulating the lock from the outside to rescue him.

  We have already proposed, for example in European patents 291,220, 509,682 and 536,653, and document DE-A-3,828,354, coupling mechanisms making it possible to avoid the aforementioned drawback by adopting a particular structure for the trainer used in the cylinder. Unfortunately, all these devices have a large number of parts, which generates difficulties in

  assembly, on the one hand, and a high cost price, on the other.

  The present invention therefore aims to provide a cylinder having a coach structure, which is simple and inexpensive to produce and which leads to easy assembly, while allowing the cylinder to be maneuvered from one side when the key is in

place on the other side.

  To this end, the subject of the present invention is a safety cylinder for a lock comprising two barrels each consisting of a stator and a rotor capable of pivoting about an axis relative to the stator, each rotor comprising a key housing. in which protruding keying means, the key associated with the rotor allowing the declaving of the rotor relative to its associated stator, the two rotors being coaxial and cooperating with a single rotary bit which is disposed between them and can be driven by means of a drive by one or the other of the two rotors for the operation of the lock, said

  coach being carried by the bit and consisting of two half

  coaxial coaches each associated with one of the two rotors, these two half-coaches being capable of relative translation and being elastically returned to the relative position which they occupy in the absence of a key, the two half-coaches being free in rotation relative to each other, and the trainer being capable of translation along the common axis of the two rotors under the action of at least one key associated with at least one of the rotors for come into a position where it performs a mechanical fastening in rotation between the bit and at least one of the rotors by mechanical engagement between, on the one hand, the bit and, on the other hand, at least one of the half trainers, characterized in that the trainer is equipped with a single spring

  consisting of a central portion inserted between the two half

  coaches to keep them elastically spaced from each other, from two intermediate portions extending on either side of the portion

  central, each intermediate portion being housed through the half

  associate coach to ensure a link between the two half

  coaches, and two external portions extending from the intermediate portions, each external portion bearing on an axially external face of the associated half-coach, the free end of each external portion being intended to cooperate with a key tip for move the trainer in axial translation, the external portions of the

  spring having a stiffness greater than that of the central portion.

  Advantageously, the intermediate portions of the spring consist of a winding with contiguous turns. Thus, the intermediate portions serve for guiding in axial translation of

  the coach and allow to create a bit and a half subset

  coaches to facilitate assembly. The central portion of the spring may consist of a winding with non-contiguous turns, the end turns of which bear on the internal faces facing the two half-coaches. Advantageously, the external portions of the spring consist of a winding with non-contiguous turns. Preferably, the winding of the central portion of the spring has an average diameter greater than that of the external portions. The outer portions and the central portion absorb the excess of

  key stroke relative to the trainer.

  In a particular embodiment, the winding of the central portion has a substantially tapered shape and the winding of each external portion can have a substantially frustoconical shape whose large base is supported on an axially external face of the coach associated and the small base is turned towards the respective rotor. Advantageously, the winding of each intermediate portion has a constant diameter less than the turn of the central portion and the turn of the external portion which bear against the

associate half-coach.

  Provision may be made for the bit to have a cylindrical collar, which is carried by the ends of the two rotors and held axially with respect to them, said collar being provided with a median web o an orifice is formed, the profile of which corresponds to the common profile of each half-trainer to allow the engagement of one or the other of the half-trainers through the veil for positioning

relative angular determined.

  Advantageously, the axial travel of the half-coaches is limited so that each half-coach cannot extend

  substantially beyond the mean plane of the median of the bit.

  It can be provided that the two half-coaches are identical and comprise at their periphery two diametrically opposite projecting lugs of different cross section, so that the bit can only be driven by a half-driver for a single angular relative position of said bit with respect to audit

  half-coach. For example, the two pins of the same half

  coach can be in the form of curved lobes which

  are the inverse image of each other in a mirror.

  Advantageously, the central portion of the spring ensures,

  in its rest position, an axial spacing between the two half

  coaches between half and the thickness of the bit wall.

  Preferably, each half-coach comprises on the axially external face of at least one lug a recess, for example in V, in the extension of the key housing of the associated rotor to allow the crushing of the external portion of the spring and l complete insertion of the key, when the half-coach is in

  an angular position which does not allow it to penetrate the veil.

  Advantageously, the free end of at least one of the external portions of the spring is bent towards the center, to prevent the end of the key from unwinding the spring by turning the key in the wrong direction, while the opposite key keeps fixed the other extremity

spring.

  Preferably, each rotor has, at its end adjacent to the bit, an open cylindrical recess, on the one hand, over its entire face facing the bit and, on the other hand, along two slots in its side wall , at least one of the two lugs of each half-coach extending radially so as to be able to engage in a slot of its associated rotor to ensure the connection in rotation between said rotor and said half-coach, the axial dimension cylindrical recess being sufficient to contain one of the two half-coaches and thus prevent the half-coach contained in the

  chambering does not come into engagement with the bit.

  In known manner, the bit can be maintained relative to the two rotors by means of two circlips arranged in grooves

  peripherals of the rotors, on either side of the collar of the bit.

  To better understand the object of the invention, we will now describe it, by way of purely illustrative example and not

  limiting, an embodiment shown in the accompanying drawing.

  In this drawing: - Figure 1 shows, in elevation, a safety cylinder according to the invention, the representation being made with cutaway so that the central zone of the cylinder appears in axial section; - Figure 2 shows an axial view of the bit of the cylinder of Figure 1; - Figure 2A shows, in perspective, the bit of Figure 2; Figure 3 is a top view of the outer face of a half-drive of the cylinder of Figure 1;

  - Figure 3A is a side elevational view of the half

  trainer of Figure 3 along arrow A; - Figure 3B is a perspective view of the internal face of the half-drive of the cylinder of Figure 1;

  FIG. 3C is a perspective view of the half

  trainer of Figure 3B, along arrow C;

  FIG. 3D is a perspective view of the half

  coach of Figure 3; - Figure 3E is a side elevational view of a lug of the half-coach of Figure 3D according to arrow E; FIG. 4 is a side elevation view of the cylinder drive of the invention, equipped with its spring; - Figure 5 is an elevational view of the spring of Figure 4; - Figure 5A is a top view of the left end of the spring of Figure 5; - Figure 6 shows in axial section the central area of the cylinder of Figure 1, a key being inserted in the key housing of the right rotor; FIG. 7 is a view similar to FIG. 6, but showing an additional key inserted into the left rotor; and - Figure 8 is a view similar to Figure 6, except that the right rotor key has rotated by an angle of about 90 and that a key

  additional was introduced into the left rotor.

  Referring to the drawing, it can be seen that the two stators of the stator block 1 of a safety cylinder comprising two barrels have been designated by la and lb. In general, the safety cylinder, which is described here, has identical elements for its right part and its left part in the drawing: the index a is assigned to the references of the organs of the left part and the index b for the references of the organs on the right, the reference figures adopted being the same for the same organs. The stator block 1 constitutes a longitudinal beam in the median axial plane of which are arranged the keying devices not shown, which allow angularly immobilizing a rotor 2a, 2b placed in each of the stators la, lb respectively. Each rotor comprises, in known manner, a key housing 3a, 3b respectively, the teeth of the key ensuring the release of the aforementioned keying means. Each rotor has, at its end disposed in the central zone of the safety cylinder, a cylindrical recess and opening on the outside, on the one hand, by its end face facing the other rotor and , on the other hand, by two longitudinal slots

diametrically opposite.

  Each rotor 2a, 2b has externally, in the area of the bottom of its recess, a peripheral groove at the bottom of which opens the slots. A circlip 6a, 6b is inserted in the groove and comes to block each rotor longitudinally inside its associated stator. Between the two circlips 6a, 6b is disposed the bit 7

of the safety cylinder.

  Conventionally, the bit 7 comprises a cylindrical collar 8, which is carried by the two ends of the rotors 2a, 2b, said collar being provided with a median web 9. The bit 7 also comprises, arranged radially relative to the collar 8, an operating tab 10, which cooperates with the members of the lock with which the safety cylinder is associated. The web 9 has in its central zone an orifice 11 consisting of a circular part 110 on which two slightly curved radial parts 111, 112 are diametrically opposite; the radial parts 111, 112 have different profiles and are for example the inverse image of one another in a mirror. The collar 8 has at its two axial ends an internal annular counterbore 4a, 4b respectively, to receive the two circlips 6a, 6b, from which it follows that the bit 7 is perfectly positioned longitudinally relative to the stator block 1 and to the two rotors 2a, 2b. The driver 12 of the cylinder of FIG. 1 is made up of two identical half-drivers 12a, 12b. Each half-coach consists of a circular ring 14a, 14b which extends at its outer periphery by a cylindrical barrel 13a, 13b extending over an angular sector greater than 180. From the external cylindrical barrel 13a, 13b, project radially outward two lugs or lobes a, 15b and 16a, 16b diametrically opposite. At their radially outer end, each lobe 15a, 15b and 16a, 16b has an active edge 115a, 11512 and 116a, 116b intended to engage radially in the opposite longitudinal slots of the associated rotor 2a, 2b regardless of the axial position of the half-coach 12a, 12b, and forms 215a, 215b and 216a, 216b which have a profile corresponding respectively to the curved radial parts 111 and 112 of the orifice 11 of the bit 7. At least one lug 116a, 116b of each half driver 12a, 12b has from its axially outer face a radially extending slot 17a, 17h, for example having a V-shaped profile intended to receive the end of a key, as explained below. This slot 17a, 17b crosses the wall of the cylindrical barrel 13a, 13b in line with the through bore 18a, 18b of the ring 14a, 14b. The two half-coaches 12a, 12b have axially internal faces 19a, 19b intended to be in facing relation, and axially external surfaces 114a, 114b facing the respective rotor 2a, 2b. A counterbore 119a, 119b is

  formed on the faces 19a, 19b around the respective bore 18a, 18b.

  In addition to the two half-coaches 12a, 12b, the coach 12 consists of a single spring 20 which is better represented in FIGS. 4 and 5. The spring 20 comprises a central winding 21 with non-contiguous turns, including the turns of end 21a, 21b bear on the counterbores 119a, 119b of the internal faces opposite 19a, 19b of the two half-coaches 12a, 12b, each end turn 211, 21k being extended by a respective intermediate winding 22a , 22b with contiguous turns, each intermediate winding being housed in the respective bore 18a, 18b of the associated half-coach. Each intermediate winding 22a, 22b is extended by an external winding with non-contiguous turns 23a, 23b, each external winding supported by an end turn 24a, 24b on the external annular surface 114a, 114b of the associated half-coach and having a respective free end 25a, 25b, one of which 25a is bent

  toward the center, as seen in Figure 5A.

  Each intermediate winding, for example the intermediate winding 22a, has a substantially constant diameter and less than that of the end turn 21a of the central winding 21 and of the end turn 24a of the external winding 23a, this which allows sandwiching between the turns 211 and 24a the ring 14a of the half-coach 12a which is thus coupled to the

spring 20.

  The central winding 21 has a progressively increasing diameter from its end turns 21a, 21b

  to its center, defining an overall curved or spindle shape.

  Conversely, each external winding 23a, 23b has a progressively decreasing diameter in the direction of the associated rotor, thus defining a substantially frustoconical shape. As the central winding 21 has a diameter greater than that of the external windings, the latter have a greater stiffness than the central winding 21 which will therefore be compressed in priority to

  external windings 23a, 23b, under the action of the push of a key.

  We will now briefly describe the assembly of the spring 20 with the driver 12 and the bit 7. The free non-bent end 25b of the spring 20 is inserted through the bore 18_ of the half-driver 12b from its internal face 19b. For this purpose, a clamp is used to lengthen the external winding 23b of the spring so that the thickness of the ring 14b penetrates into the inter-turn spacing of the external winding 23b, which makes it possible to screw the external winding 23b through the half-coach 12b, until its end turn 24b is in abutment against the external annular face 114b of the half-coach 12b. The intermediate winding 22b having a length substantially equal to the axial length of the bore 18b, the end turn 21b of the central winding 21 is in abutment against the

  counterbore 119b of the internal face 19b of the half-coach 12b.

  Contrary to what is shown in FIG. 4, it is then

  necessary to mount the bit 7 on the internal face 19b of the half

  coach 12k, before assembling the other half-coach 12a, otherwise it would no longer be possible to mount the bit 7 from the assembly

in Figure 4.

  The other half-driver 12a is then mounted on the end a of the spring 20. However, due to the presence of the bit 7 between the two half-drivers, it becomes difficult to use the pliers to screw in the same way the external portion 23a of the spring to

through the half-coach 12a.

  A rod is then used having a beveled end which engages through the assembly of the two half-coaches 12a, 12b and of the spring 20, from the non-bent end 25b of the spring 20. When the beveled end of the rod is inserted into the half-opening 26 defined by the curved end 25a of the external winding 23a, an axial thrust is exerted on the rod while carrying out a rotation, which has the effect of allowing the crossing

  of the bore 18a of the half-driver 12a by the external winding 23a.

  In addition, the presence of such a curved end 25a makes it possible to prevent a tip of the key from unwinding the spring 20 by turning the key in the wrong direction, while an opposite key keeps 11 fixed the other end 25b spring. In other words, thanks to this curved end 25a, it is not possible to exert a force of

  reverse torsion on both ends of the spring.

  We will now describe the operation of the safety cylinder of the invention, with reference to Figures 6 to 8. In this operation, the keys associated with the rotors 2a, 2b are respectively designated by the references 100_, 0l0b. For the rest

  from the description, it will be assumed that the rotor 2b is disposed on the side

inside the door.

  When the key 100b is introduced into the rotor 2b; as shown in Figure 6, the end 10lb of the key 100b bears against the free end 25b of the spring 20, penetrating inside the radial slot 17b of the half-coach 12b, which slot 17b is aligned with the key housing 3b of the rotor 2b, which pushes the assembly of the driver 12 to the left in FIG. 6 and brings the parts 215b, 216b of the lugs 15b and 16b of the half-driver 12b inside the orifice 11 in the median web 9 of the bit 7, so that the half-driver 12b is engaged with the bit 7; in addition, the parts 115b and 116b of the pins 15b, 16b remain inside at least one of the slots of the rotor 2b, from which it follows that the rotor 2b can rotate the half-driver 12k and , therefore, the bit 7; such a rotation is possible since the key 100b could have come, thanks to the displacement of the half-coach 12b in its position

  maximum penetration allowing the declaving of the rotor 2b.

  Simultaneously, the half-driver 12a has been positioned completely outside of the web 9 of the bit 7 and is fully engaged inside the slots of the rotor 2a, so that a rotation of the bit 7 can be carried out without any modification of the angular position of the half-coach 12a, which remains in place. The operation of the safety cylinder was thus carried out from one of the barrels, without the position of the rotor 2a of the other barrel having been modified, that is to say that the rotor 2a is in the position where the key can be inserted. The parts 215b, 216b which penetrate inside the veil 9 of the bit 7 have an axial length substantially equal to half the thickness of the veil 9, to allow, as indicated below, the two half-coaches to penetrate into the veil. In addition, the central winding of the spring 20 has at rest an axial length slightly greater than the half thickness of the web 9 of the bit 7, so that in the position of Figure 6, the half-coach 12a is completely disengaged from the web bit. Of course, the respective recesses of the rotors 2a, 2k have a length sufficient to allow the displacement of the half-coaches 12a, 12k over a stroke approximately equal to half the thickness of the web 9 of the bit 7. The active edges 115b and 116k of the pins 15b and 16k of the trainer 12b can serve as an end-of-travel stop for introducing the half-trainer 12b inside the orifice 11 of the

veil 9 of bit 7.

  If a second key 100a is then introduced into the rotor 2a, the end of the key 101a will bear on the free end 25a of the spring 20, which pushes the half-driver 12a to the right on the

  Figure 7 to engage the latter with the blade of the bit 7.

  The central winding 21 of the spring 20 is in this fully compressed position between the two half-coaches 12a and 12k inside the countersinks 119a and 119b provided around the bores 18a and 18b on the internal surface 19a, 19b of each half coach. As the stiffness of the external windings is greater than that of the central winding 21, the latter will be compressed by the keys 100a and b allowing the engagement of the two half-coaches with the

bit 7.

  FIG. 8 represents the same members as FIG. 7, after the key 100b has subjected the bit 7 to rotate by an angle of 90 in a clockwise direction. When the key 100a is inserted into the rotor 2a, the flat end 101a of the key will bear on the end

  free 25a of the spring 20 by engaging in the slot 17a of the half

  coach 12a. In the position of FIG. 8, the internal face 19a of the half-coach 12a bears against the web 9 of the bit 7, without being able to penetrate into the orifice 11 because their relative angular position is offset. Consequently, the external winding 23a will be compressed by the end of the key 101a allowing the complete introduction of the key 100a. If the key 100a is then turned, nothing prevents the rotation of the rotor 2a and of the half-driver 12a relative to the bit 7. It is thus possible to bring the key 100a to the position which corresponds to the position of the key 100b, at which case, the lugs of the half-coach 12a come in line with the corresponding radial parts 111, 112 of the orifice 11 of the bit 7, which allows the lugs 15a and 16a of the half-coach 12a to penetrate inside the orifice 11 under the action of the external winding of 23a thus compressing the central winding 21, in a manner similar to that shown in FIG. 7. In the position of FIG. 8, the key 100b is not in a position where it can be extracted from its key housing, but when the key 100a has also been turned by an angle of 90, any subsequent action of rotation on the key 100a will cause the bit 7 and, simultaneously, the half-coach 12b, the rotor 2b and the key 100b. This drive can be maintained until one is in the open position of the lock and the two rotors 2a, 2b are

  returned to their rest position which allows the extraction of the key.

  We see that it has thus been possible, thanks to the particular structure of the driver 12, the operation of the safety cylinder while the key 100b was engaged in the corresponding barrel and there

  was blocked by the rotation of the rotor 2b_.

  It will be noted in FIG. 8 that the keys used can be of the movable type displaceable in an orifice 102b extending in the plane of the end of the key 101b. Of course, another type of key could

also be used.

  Although the invention has been described in connection with a particular embodiment, it is obvious that it is in no way limited thereto and that it includes all the technical equivalents of the means described as well as their combinations if these are within the scope of the invention.

Claims (15)

  1. Safety cylinder (1) for lock comprising two barrels each consisting of a stator (la, 1) and a rotor (2a, 2) capable of pivoting about an axis relative to the stator, each rotor comprising a key housing (3a, 3b) in which protruding keying means, the key (100a, 100b_) associated with the rotor allowing the unlocking of the rotor relative to its associated stator, the two rotors being coaxial and cooperating with a bit single rotary (7) which is arranged between them and can be driven by a driver (12) by one or the other of the two rotors for the operation of the lock, said driver being carried by the bit and consisting of two coaxial half-coaches (12a, 12b) each associated with one of the two rotors, these two half-coaches being capable of relative translation and being elastically returned to the relative position which they occupy in the absence of a key , the two half-coaches were nt free to rotate relative to each other, and the driver being capable of translation along the common axis of the two rotors under the action of at least one key associated with at least one of the rotors to come into a position where it achieves mechanical attachment in rotation between the bit and at least one of the rotors by mechanical engagement between, on the one hand, the bit and, on the other hand, at least one of the half-coaches, characterized in that the coach (12) is equipped with a single spring (20) constituted by a central portion (21) interposed between the two half-coaches (12a, 12b) to hold them elastically spaced from each other, two intermediate portions (22a, 22b) extending on either side of the central portion, each intermediate portion being housed through the associated half-coach to ensure a connection between the two half-coaches, and two external portions (23a, 23b) extending through shooting of the intermediate portions, each external portion bearing on an axially external face (114a, 114b) of the associated half-coach, the free end (25a, 251) of each external portion being intended to cooperate with a key tip (101a , 101b) for moving the driver in axial translation, the external portions of the spring having a stiffness   greater than that of the central portion.   2. Cylinder according to claim 1, characterized in that the intermediate portions (22a, 22k) of the spring (20) are   consisting of a winding with contiguous turns.   3. Cylinder according to claim 1 or 2, characterized in that the central portion (21) of the spring (20) consists of a winding with non-contiguous turns whose end turns (21a, 211) are supported on the internal faces (119a, 119k) facing the two half-coaches (12a, 121).   4. Cylinder according to one of claims 1 to 3,   characterized in that the external portions (23a, 231) of the spring   (20) consist of a winding with non-contiguous turns.   5. Cylinder according to claims 3 and 4, characterized by   the fact that the winding of the central portion (21) of the spring (20) has a   mean diameter greater than that of the external portions (23a, 231).   6. Cylinder according to claim 3 or 5, characterized in that the winding of the central portion (21) has a shape substantially in a spindle.   7. Cylinder according to claim 4 or 5, characterized in that the winding of each external portion (23a, 231) has a substantially frustoconical shape whose large base (24a) is supported on an axially external face (114a, 114k) of the associated coach (12a, 121) and the small base (25a, 25k) is turned towards the respective rotor (2a, 2k).   8. Cylinder according to claims 2 to 4, characterized by   the fact that the winding of each intermediate portion (22a, 221) has a constant diameter less than the turn (21a, 21k) of the central portion (21) and the turn (24a, 24b) of the outer portion (23a , 23k)   which bear against the associated half-coach (12a, 12k).   9. Cylinder according to one of claims 1 to 8,   characterized in that the bit (7) comprises a cylindrical collar (8), which is carried by the ends of the two rotors (2a, 2k) and held axially relative to them, said collar being provided with a median web ( 9) o is an orifice (11), the profile of which corresponds to the common profile of each half-coach (12a, 12k) to allow the engagement of one or other of the half-coaches to   through the web for a determined relative angular positioning.   10. Cylinder according to claim 9, characterized in that the axial stroke of the half-coaches (12a, 12k) is limited so that each half-coach cannot extend substantially   beyond the mean plane of the median web (9) of the bit (7).   11. Cylinder according to claim 9 or 10, characterized in that the two half-coaches (12a, 12b) are identical and comprise at their periphery two diametrically opposite projecting lugs (15a, 15b, 16a, 16b_) of different cross section , so that the bit (7) can only be driven by a half-coach for a single angular relative position of said bit relative to said half-coach. 12. Cylinder according to claim 11, characterized by   causes the two pins (15a, 15b, 16a, 160) of the same half   coach (12a, 12_) are in the form of curved lobes (215a, 215b, 216a, 216b) which are the opposite image of each other in a mirror.   13. Cylinder according to one of claims 11 and 12,   characterized in that each half-driver (12a, 12b) has on the axially external face of at least one lug (16a, 16b) a recess (17a, 17b), for example in V, in the extension of the housing of key (3a, 3b) of the associated rotor (2a, 2b) to allow the crushing of the external portion (23a, 23b) of the spring (20) and   the complete introduction of the key (100a, 100h), when the half   coach is in an angular position which does not allow him to penetrate the veil (9).   14. Cylinder according to one of claims 9 to 13,   characterized in that the central portion (21) of the spring (20) ensures, in its rest position, an axial spacing between the two half-coaches (12a, 12k) between half and the thickness of the veil (9) of the bit (7).   15. Cylinder according to one of the preceding claims,   characterized in that the free end (25a) of at least one (23a) of the external portions (23a, 23b) of the spring (20) is bent towards the center.