Combination disk lock comprising means for automatic scrambling on locking

A lock comprising notched combination disks, a bolt movable in translation and urged to its extended position which may be moved solely when a coded combination has been formed by rotation of the combination disks, and means for driving the bolt to its retracted position. In accordance with the invention, the lock comprises means for locking the bolt in the retracted position, means for making said bolt drive means inoperative when the bolt is in its retracted position, and means for unlocking the bolt once the door has been opened then closed again.

BACKGROUND OF THE INVENTION 
The invention relates to a lock fitted to a door and comprising a bolt 
movable in a straight line between an extended position and a retracted 
position, means for urging the bolt to its extended position, means for 
returning the bolt from its extended position to its retracted position, 
movably coupled to the bolt, a combination disk, comprising a notch and 
stop means, mounted for rotation on a shaft, a drive disk mounted for 
rotation on said shaft comprising stop means cooperating with those of the 
combination disk in a given relative angular position of these disks, and 
first means for cooperating with said bolt traction means, means for 
rotating the drive disk, second means for cooperating with said bolt 
traction means, adapted so as to be received in said notch in a given 
angular position of the combination disk, obtained by actuating said 
operating means in accordance with a coded combination, these second means 
being movable between a position in which they are situated outside the 
notch and hold the bolt traction means away from the drive disk and a 
position in which they are situated in the notch and allow cooperation 
between the bolt traction means and said first means of the drive disk, 
the bolt then being able to be moved to its retracted position by rotation 
of the drive disk. 
A lock of this type is known more particularly from the document US-A-4 147 
045 and operates satisfactorily. 
However, it reveals a few drawbacks in use. 
In such a lock, the bolt is held in a retracted position by the user who 
immobilizes the means for operating the drive disk, for example an 
operating handle. Since the bolt traction means cooperate with the drive 
disk, they are prisoners of this latter and effectively retain the bolt in 
the retracted position. 
At this stage, the authorized user may block the operating handle by any 
appropriate means for preventing subsequent closure of the lock and thus 
avoid having to dial the coded combination the next time he accedes to the 
door. 
In addition, when a finger is provided for scrambling the combination disk, 
mounted on the bolt for striking the combination disk when the bolt is 
extended, the user may try to partially neutralize the scrambling effect 
by braking the movement of the operating handle when it returns to an 
angular position corresponding to closure of the door, namely by braking 
the movement of the bolt traction means. 
SUMMARY OF THE INVENTION 
The problem which the invention attempts to solve is then that of 
separating the operating handle from the bolt once the lock has been 
opened. 
This problem is solved by providing in the lock means adapted for locking 
the bolt in its retracted position, means for moving the bolt traction 
means away from the drive disk when the bolt is in the retracted position, 
and means adapted for unlocking the bolt once the door has been opened 
then closed again. 
Advantageously, the bolt locking means comprise a rocking lever mounted for 
pivoting in the bolt and returned resiliently towards the bolt, and stop 
means mounted on the rocking lever and adapted for cooperating with stop 
means provided on the bolt, and said bolt unlocking means comprise a 
pusher mounted for pivoting on the rocking lever and adapted for 
cooperating with a door casing or a mobile keeper during closure of the 
door so as to cause the rocking lever to pivot so as to move said stop 
means of the rocking lever away from the bolt. 
Advantageously, said means for moving away the bolt traction means comprise 
a finger mounted for pivoting on the bolt, a spring mounted fixedly in the 
lock and adapted for cooperating with the finger when the bolt is in the 
retracted position, sO as to return the finger in a direction of rotation 
in which this latter moves said bolt traction means away from the drive 
disk. 
Advantageously, the lock comprises an auxiliary bolt movable in a straight 
line between an extended position and a retracted position and means for 
urging it to its retracted position said drive disk being in contact with 
the auxiliary bolt and adapted for cooperating therewith so that, with 
said bolt in the retracted position, the auxiliary bolt is in its extended 
position if the drive disk is in an angular position in which it 
cooperates with said bolt traction means and the auxiliary bolt is in its 
retracted position in the opposite case. 
Advantageously, the lock comprises scrambling means for modifying randomly 
the angular position of the combination disk on closure of the door, these 
scrambling means comprising a finger mounted on the bolt so as to be able 
to pivot parallel thereto and be urged towards the combination disk, said 
finger penetrating into said notch in the combination disk when the bolt 
is in the retracted position and driving the combination disk over a 
random angular portion when the bolt moves to its extended position.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The lock shown in the figures comprises a parallelepipedic case 1 formed of 
a bottom 2 and four sidewalls 3, 4, 5 , 6. As shown in the figures, the 
case is oriented in use so that its bottom 2 and its two opposite 
sidewalls 3, 5 are vertical. The vertical wall 3 comprises two rectangular 
apertures 7, 8 disposed at the side of each other and extending 
vertically. 
Bottom 2 has, in three of its corners, a hole 9, 10 and 11 for fixing to a 
door and, in its central part, a hole 12. It further has a pluralitY of 
posts 13 to 19 extending perpendicularly and several studs 20 to 22, post 
19 having a collar 19a at its base. 
A reciprocating assembly 30 comprises a plate bent into an L shape so as to 
define two vertical faces 31, 32. Face 31 has two oblong holes 33, 34 
formed side by side and extending vertically, whose dimensions are adapted 
for receiving respectively post 13 and the collar 19a of post 19 of case a 
finger 35 extending horizontally in the plane of face 31 from its edge 
opposite the other face 32, a lower notch 36 adjacent the bend of the 
reciprocating assembly 30 and an upper notch 37. ,Face 31 of the 
reciprocating assembly 30 further comprises a perpendicular finger 38 
disposed above and in line with the oblong hole 33. 
A projection 41 carried by face 31 forms, with face 32, a fork receiving a 
horizontal shaft 42 parallel to face 31. A mobile wedge 45 and a helical 
spring 43 are mounted side by side on shaft 42 (figures 1a and 5). Spring 
43 bears by one end on face 31 and by the other end on a laterally 
projecting shoulder 46 provided on the mobile wedge 45. 
The mobile wedge 45 has a recess 47 opening both into its upper face and 
its side face opposite shoulder 46, which is intended for cooperating with 
a stop pin 44 projecting perpendicularly from face 32. The mobile wedge 45 
is therefore returned resiliently to a horizontal position in which it 
abuts the stop pin 44, but it may be pushed downwards so as to pivot in a 
clockwise direction (FIG. 5) through a certain angle at least. 
The reciprocating assembly 30 is intended to be applied on the bottom 2 of 
case 1 by means of a spacer 39 in the form of a cylinder mounted on post 
19 and whose outer diameter is greater than the oblong hole 34. Spacer 39 
is fixed by screw 40 cooperating with a threaded portion of post 19. The 
reciprocating assembly 30 bears against the two studs 21, 22 of case 1 so 
that it can only make a vertical translational movement between a top 
position (FIG. 2a) and a bottom position (3a) in each of which one end of 
the oblong holes 33, 34 abuts respectively against post 13 and against the 
collar 19a of post 19. 
A rocker arm 50 in the form of an L disposed in a vertical plane has two 
holes 51, 52, a perpendicular finger 53 disposed at the lower part of the 
rocking lever 50 and a perpendicular projection 54. A pusher 55 has a 
thickened portion 56 at one end, a rounded portion 57 turned downwardly at 
the opposite end and a hole 58 in a central region. A pin 59 passes 
through hole 58 of pusher 55 and hole 51 of the rocking lever 50. The 
rocking lever 50 is mounted for rotation by its hole 52 on post 17 of case 
1, between a straight position (FIG. 3a) and an inclined position (FIG. 
2a). It is returned resiliently to the straight position by a helical 
spring 60 mounted on post 15 and one end of which bears on post 18 of the 
case and the other end on a sidewall of the rocking lever 50. Rotation of 
the rocking lever 50 in a clockwise direction is limited by stud 20 
against which the upper part of the rocking lever abuts its rotation in an 
anti-clockwise direction is limited by the sidewall 3 of case 1. The 
pusher passes, with its rounded end 57, through aperture 7 in all the 
angular positions of the rocking lever 50. It may pivot with respect to 
the rocking lever 50 about the pin 59. Because of the presence of its 
thickened portion 56, the pusher 55 tends to rotate in a clockwise 
direction under the effect of gravity. Its rotation in an anti-clockwise 
direction is only limited by the upper part of sidewall 3 of the case, 
against which its thickened portion 56 will abut. Its rotation in a 
clockwise direction is limited either by projection 54 of the rocking 
lever 50 against which it abuts when the rocking lever is in the vertical 
position (FIG. 3a), or by the upper edge of the aperture 7 against which 
it abuts when the rocking lever 50 is in the inclined position (FIG. 2a). 
A bolt 70 with the general shape of an L on its side comprises a front 
parallelepipedic end 71 intended to pass through the aperture 8 in case 1 
for cooperating with a bar operating device described subsequently. It has 
a stop face in the extended position 72 and a stop face in the retracted 
position 73 which are vertical and turned towards the parellelepipedic end 
71 and a slanted stop face 74 turned towards its rear end which is 
intended to cooperate with the finger 38 of the reciprocating assembly 30. 
On its main face turned outwardly of case 1, bolt 70 has two studs 75, 76 
adjacent the front end 71 and a stud 77 adjacent the rear end. On its main 
face opposite thereto, it has a rear stud 78 disposed lower and more to 
the rear than stud 77 (FIG. 2b), and a vertical shoulder 79 which means 
that the rear part of bolt 71 is thinner than its front part (FIGS. 8 and 
9). 
A scrambling finger 80 has a hole 82 by which it is mounted for pivoting on 
stud 78 of bolt 70 by being rotated towards the front end 71 of the bolt. 
On its main face turned towards the bottom of case 1 and in its upper 
part, the scrambling finger 80 comprises a projecting shoulder 81 
extending horizontally. 
A traction hook 90 has at one end a hole 93 and, at the opposite end, and 
on its main face turned towards the bottom of case 1, a projecting 
shoulder 91 extending along a curved line, as shown in FIGS. 4b and 9. 
This hook is mounted for pivoting on stud 76 of bolt 70, so as to be 
turned rearwardly of the bolt and with interpositioning of a spacing 
washer 92 whose thickness corresponds to that of shoulder 91 of the 
traction hook 90. 
A disengagement finger 94 has a hole 95 by which it is mounted for pivoting 
on stud 77 of bolt 70. A spacing washer 96 is also mounted on stud 77 so 
as to cap the disengagement finger 94. 
A blade spring 85 having a general V shape has two branches, one of which 
is deformed so as to form a gripper 86 for surrounding post 14 of case 1. 
A spacing washer 97 has a re-entrant shoulder at both ends, one being 
received in hole 11 at the bottom of case 1 and the other receiving a 
helical spring 98. 
Bolt 70, equipped with the scrambling finger 80, with the traction hook 90 
and the disengagement finger 94 is disposed in case 1, in front of the 
reciprocating assembly 30 and the rocking lever 50. These parts are shown 
in FIG. 8, where it can be seen that the shoulder 79 of bolt 70 
advantageously allows the scrambling finger 80 to be partiallY housed. 
Bolt 70 may be moved in a straight line in case 1 between an extended 
position (FIG. 2b) and a retracted position (FIG. 3b). In these two 
positions, its front end 71 bears on the lower edge of the aperture 8 of 
case 1. Furthermore, the blade spring 85 bears by one of its branches on 
the sidewall 4 of the case and by the other on stud 75 of bolt 70, so that 
the bolt 70 is returned resiliently to its extended position. As will be 
mentioned hereafter, the rear part of the bolt is supported by an aperture 
191 in a plate 190 covering the lock. In addition, in the retracted 
position of bolt 70, the helical spring 98 bears by one of its ends on the 
sidewall 5 of the case and by the other end on the disengagement finger 94 
and tends to cause this latter to pivot in a clockwise direction. 
In the extended position, bolt 70 abuts with its stop face 72 against the 
sidewall 3 of the case. Before the combination of the lock has been formed 
for opening it (FIGS. 2a and 2b) and as mentioned hereafter, the 
reciprocating assembly 30 is in the top position and the mobile wedge 45 
which it carries is then situated behind the rear end of bolt 70 : it 
follows that bolt 70 cannot be pushed manually towards its retracted 
position for it would abut against the mobile wedge 45. On the other hand, 
once the combination is formed, bolt 70 may be retracted at most until it 
abuts with its rear end against the spacer socket 97. 
In a way known per se, the lock comprises several apertured combination 
disks 100 (figures 1b and 2a), which are open along a radial slit 101 and 
which have a notch 102 on their radial outer edge; in accordance with the 
invention, however, one of the ends 103 of the notch is connected to the 
outer edge of the disk along a radius intended to cooperate with finger 38 
of the reciprocating assembly 30. In line with slit 101, each combination 
disk has a hole 104 for moving it away by means of a key. Apertured cores 
110, whose outer diameter is a little greater than the inner diameter of 
the combination disks, may thus be mounted by resilience therein. Each 
core has on one face a finger 111 parallel to the axis of the core and on 
the other face an annular flange 112 itself carrying a finger 113 
extending radially outwardly. 
In a way also known per se, the lock comprises secondary apertured drive 
disks 120, having on their radially inner edge a notch 121 and, opposite 
thereto, a finger 122 extending parallel to the axis of the disks. 
Furthermore, a main drive disk 130 (FIGS. 1b and 3b) is provided whose 
structure is specific to the present invention. It is formed of two disks 
140, 150 applied permanently one against the other and having different 
outer diameters, the smallest diameter disk 140 having a cut-out 141 
opening outwardly and towards its radially outer edge, disk 150 having a 
similar cut-out 151 disposed in line with the cut-out 141, and whose 
bottom 152 extends peripherally along an arc of a circle of a radius equal 
to the radius of the other disk 140. The cut-out 151 extends over an 
angular portion greater than that along which cut-out 141 extends. 
Moreover, disk 140 has a circular central thickened portion 142 and disk 
150 has a finger 153 parallel to its axis. Finally, the main drive disk 
130 as a whole comprises a through hole 131 of square section. 
An apertured spacer disk 160 has, seen in a top view, an external shape and 
size identical to those of disk 150, so in particular cut-out 161. It has 
in addition, an aperture 162 extending along a circle portion defined by 
an angular sector a little greater than that along which the cut-out 151 
in disk 150 extends. 
Spacer plates 170, known per se, are interposed between the combination 
disks 100 and the secondary drive disks 120 on the one hand ,and between 
the spacer disk 160 and the secondary adjacent drive disk 120. Some have 
bosses 171 distributed peripherally for bearing on the adjacent spacer 
plate or on the spacer disk 160. Each spacer plate has two lower holes 172 
through which pass the posts 15, 16 of case 1 and a mid-height hole 173 
disposed opposite the hole 104 in the combination disks 100. 
The combination disks 100, cores 110, the main 130 and secondary 120 drive 
disks and the spacer plates 170 are fitted on the post 13 of case 1, with 
previous interpositioning of a washer 180. A cover plate 190 holds all the 
parts of the lock applied against each other in case 1. It is held in 
position by screwing on to the three posts 14 to 16 of the case. It has a 
horizontal aperture 191 in its right hand upper part which is intended to 
guide and support stud 77 of bolt 70 during the translational movement 
thereof. 
The lock as a whole is fixed to a door panel 200 by means of threaded posts 
201 secured to this panel, one of them passing through the spacer socket 
97, these posts cooperating with nuts 202. A control knob 210 for the lock 
comprises a cylindrical surface 211 graduated circumferentially and a 
square section rod 212 passing through the door panel 200 for cooperating 
with the square hole 131 in the main drive disk 130. A cylindrical housing 
220 is adapted for receiving and masking the graduated portion 211 of the 
control knob 210. It has a notch 221 in its upper part allowing the 
graduated surface 211 to be observed solely by the user of the lock and 
positioning of the knob 210 opposite a mark 222. Housing 220 is fixed by 
appropriate means to the door panel 200 and the knob 210 is coupled to 
housing 220 by appropriate means -so as to only allow rotation of the knob 
with respect to the housing. 
In operation, when knob 210 is rotated in a clockwise direction, it drives 
the main drive disk 130. At a given moment during such rotation, finger 
153 of the main drive disk 130 abuts against one end 163 of the aperture 
162 of the spacer disk 160 and then rotates this latter. The arrangement 
is such that the notches 151 and 161 in the respective disks 130, 160 then 
occupy the same angular position. 
On the other hand, when the main drive disk 130 is rotated in an 
anti-clockwise direction, its finger 153 abuts against the other end 164 
of aperture 162 of the spacer disk 160 and then rotates this latter (FIG. 
2b). The arrangement is such that notches 151 and 161 of respective disks 
130, 160 are then offset angularly, so that notch 151 is masked by the 
spacer disk 160. 
Furthermore, and in a way known per se, finger 153 of the main drive disk 
130 abuts against the finger 122 of the secondary drive disk 120 which 
begins to rotate. When notch 121 of this disk abuts, by one end, against 
the radial finger 113 of the adjacent core 110, this latter rotates in its 
turn. Similarly, the axial finger 111 of core 110 drives the adjacent 
secondary drive disk 120, which drives the adjacent core 110. Since the 
combination disks 100 are fast with the cores 110, they rotate so that the 
angular position of their notch 102 is modified. Also in a way known per 
se, for opening the lock, it is necessary first of all to position the 
bottom-most combination disk 100 in the case so that its notch 102 is in 
the top position (FIGS. 3a and 4a), for example by rotating the knob 210 
in a clockwise direction. Then the second combination finger 100 is 
positioned by rotating the knob in an anti-clockwise direction. 
As is clear from FIG. 10, and in this embodiment, a mechanism for closing 
the door is mounted on the panel of the door, beside the case 1 of the 
lock. In a way known per se, this mechanism comprises a keeper 230 
extending substantially in the plane of the lock, which has one L shaped 
end 231 with a rectangular opening 232 for receiving the end 71 of the 
bolt 70, and another end, also with a rectangular opening 233. This keeper 
is mounted for pivoting in its plane on a shaft 234. 
Above and below shaft 234 two bars 240, 250 are mounted for pivoting by one 
end about two shafts 241, 251 and extend respectively upwards and 
downwards and are intended to cooperate with keepers provided in a casing 
of the door. A vertical bracket 260 in the form of an L has on one leg a 
pin 261 adapted for moving in the opening 233 of keeper 230 and on another 
leg two horizontal bolts 262, 263 disposed one below the other and adapted 
for cooperating with two corresponding keepers provided on the casing of 
the door. 
A handle 270 is used for rotating keeper 230. In a way also known per se, 
rotation of handle 270 in the direction of arrow 271 (FIG. 10) allows the 
bars 240, 250 and bolts 262, 263 to be driven in the direction of arrows 
272 so as to move them away from the keepers with which they cooperate, 
and rotation of the handle in the opposite direction results in causing 
them to penetrate into the keepers. 
According to the invention, the L shaped end 231 of keeper 230 has a 
perpendicular screw 235 projecting outwardly which is immobilized by a nut 
236. 
The operation of the lock as a whole will now be described. It will be 
considered that the lock is closed (FIGS. 2a, 2b). Bolt 70 is in the 
extended position, in which it penetrates into opening 232 in keeper 230. 
The disengagement finger 94 hangs under the effect of its own weight, for 
spring 98 does not cooperate with it. The relative position of the drive 
disk 130 and of the spacer disk 160 then depends on the direction of 
rotation in which knob 210 was last rotated. Such as shown in FIG. 2b, it 
has been considered that the knob has been rotated in an anti-clockwise 
direction, so that the two disks 130, 160 are offset angularly and the 
finger .38 of the reciprocating assembly 30 may then either bear on both 
of them, as shown in FIG. 2b, or bear on disk 160 alone if the knob is 
rotated through about 180.degree. in an anti-clockwise direction and if 
notch 151 faces the finger 38 of the reciprocating assembly 30. In both 
cases, finger 38 is supported at the same height so as to be situated a 
little above the combination disks 100 (FIG. 2a). With this arrangement, 
it is not possible to attempt to discover the coded combination of the 
lock by rotating knob 210: in known locks, where finger 38 rested on the 
combination disks, it was possible to hear the impact of finger 38 rubbing 
against one or other of the notches 102 of these disks. 
The reciprocating assembly is therefore in the top position so that the 
mobile wedge 45 is situated behind the bolt 70, preventing this latter 
from being pushed inwardly of the lock. The scrambling finger 80 rests by 
its shoulder 81 on the face 31 of the reciprocating assembly 30. The 
combination disks 100 are in a random angular position. 
The traction hook 90 rests by its shoulder 91 on finger 38 of the 
reciprocating assembly 30 and is therefore held in a top position not 
allowing it to penetrate into the notch 141 in the drive disk 130. 
Finally, the rocking lever 50 bears by its finger 53 under bolt 70 (FIG. 
2a) and is therefore held in a slanted position so that pusher 55 is 
almost completely retracted into the lock and is not in contact with the 
screw 235 carried by the keeper 230. 
We will now consider that the coded combination has been made by rotating 
knob 210 (FIGS. 4a and 4b) in one direction and in the other alternately, 
and for the last time in an anti-clockwise direction. Notches 102 of the 
two combination disks 100 are therefore aligned in the top position. Knob 
210 was then rotated in a clockwise direction so that notch 151 is 
progressively no longer masked by the spacer disk 160, and so that the 
finger 38 on the reciprocating assembly 30 falls on the bottom 152 of 
notch 151 whose radial distance is identical to that of the bottom of 
notches 102 in the combination disks 100 in FIG. 4a, finger 38 is 
therefore at the bottom of notches 102. 
Consequently, the traction hook 90 has pivoted under the effect of gravity 
until it abuts against the bottom of notch 141 of the main drive disk 130 
: it will in fact be noted that, in FIG. 4b, the traction hook 90 is no 
longer supported by the finger 38 of the reciprocating assembly 30. 
Another consequence is that the reciprocating assembly 30 has moved to its 
low position. The scrambling finger 80 is therefore no longer supported by 
the reciprocating assembly 30 and bears on the combination disks 100. 
Furthermore, the mobile wedge 45 has moved to its low position in which it 
no longer prevents retraction of bolt 70. 
Such as shown in FIGS. 4a, 4b, the lock is ready to be opened. It is 
sufficient to continue rotating knob 210 in a clockwise direction so as to 
drive the traction hook 90 towards the right and so cause retraction of 
bolt 70. The progressive retraction of bolt 70 has three successive 
effects : firstly the scrambling finger 80 moves back, its free end 
sliding over the combination disks 100 until it falls into the notch 102 
thereof secondly, finger 53 of the rocking lever 50 "falls" in the 
shoulder of bolt 70 defined by the stop face 73 since this finger rubs 
against the bolt while being resiliently urged to rotate anti-clockwise 
finally, since the traction hook moves rightwards (FIG. 4b), it pushes the 
disengagement finger 94 against the effect of spring 98. 
At the moment when the user releases knob 210, spring 98 causes the 
disengagement finger 94 to pivot in a clockwise direction, the 
disengagement finger itself causing the traction hook 90 to pivot in an 
anti-clockwise direction so that this latter leaves the notch 141 of the 
main drive disk 130 and comes against the sidewall 4 of the lock case 1. 
The situation then obtained is illustrated in FIGS. 3a, 3b. The bolt is 
held in the retracted position by the finger 53 of the rocking lever 50. 
It will be noted that knob 210 can then only be rotated through an angular 
portion corresponding to that over which notch 151 of the main drive disk 
extends. In fact, in one direction as in the other, the edges of notch 151 
tend to raise finger 38 now, this latter cannot be raised for it abuts 
against the slanting stop face 74 of bolt 70. This prevents an attempt by 
the user to lift finger 38 so as to lift the scrambling finger 80 and 
avoid scrambling of the combination disks 100. 
Once the lock is opened, the keeper 230 may be rotated in a clockwise 
direction (FIGS. 3a, 3b) from a horizontal position (FIG. 10) by means of 
the handle 270. In fact, the bolt 70 no longer passes through opening 232 
in keeper 230 and the screw 235 of the keeper abuts, during rotation, 
against pusher 55 which retracts while pivoting in an anti-clockwise 
direction. The door is then open. 
To close the door again, handle 270 is rotated and so is keeper 230 in an 
anticlockwise direction. Screw 235 comes into abutment against the rounded 
end 57 of pusher 55. Now, this latter cannot pivot in a clockwise 
direction since it bears against the projection 54 of the rocking lever 
50, so that the rocking lever is pushed in a clockwise direction against 
the effect of spring 60. The result is that the finger 53 of the rocking 
lever 50 is released from the stop face 73 of bolt 70 : the bolt is then 
pushed instananeously towards its extended position by the blade spring 
85. 
During extension of bolt 70, the scrambling finger 80 is driven leftwards 
in FIG. 3a, so that it pushes the combination disks 100 which rotate 
randomly through a certain angle. In practice, it has been observed that 
the different combination disks did not exactly cover the same path, so 
that their notches 102 are no longer aligned. 
Since the combination disks 100 are rotated anti-clockwise, through the 
rounded end 103 of the notch 102 they push the finger 38 of the 
reciprocating assembly 30 back to its top position. Furthermore, with the 
traction hook 90 moving away from the disengagement finger 94, it is no 
longer supported thereby and comes into abutment against finger 38 of the 
reciprocating assembly 30. 
The situation then obtained is the initial situation illustrated in FIGS. 
2a, 2b. 
In this embodiment, it has been ascertained that extension of bolt 70 takes 
place more slowly than rising of the reciprocating assembly 30. That means 
that the mobile wedge 45 abuts against the rear part of bolt 70 during 
rising of the reciprocating assembly 30. But since this wedge is mounted 
for pivoting, the mechanism of the lock is not locked, the mobile wedge 45 
being pushed back downwards through a certain angle. 
It will be noted that, in the absence of the disengagement finger 94, the 
traction hook 90 would remain in the notch 141 of the drive disk 130 after 
the lock has been opened, which would allow the user, by immobilizing knob 
210, to prevent the automatic extension of bolt 70 when closing the door. 
The result would be that the lock would not be closed and the combination 
disks 100 would not be scrambled. In fact, it is therefore preferable to 
provide a disengagement finger 94. 
In a way known per se, modification of a coded combination of the lock is 
achieved by introducing through the rear of the lock a key or rod passing 
through the hole 12 in case 1, holes 104 in the combination disks 100 and 
holes 173 in the spacer plates 170. The combination disks are then moved 
aside and their cores 110 may be rotated by operating knob 210. Finger 35 
of the reciprocating assembly 30 advantageously rests on the key during 
this operation since it is situated in line with hole 12 in case 1 (FIG. 
2a) : the reciprocating assembly 30 is therefore held in the top position, 
so that the traction hook 90 is moved away from the drive disk 130 which 
may rotate freely. 
In another embodiment of the invention, no door closure mechanism is 
provided at the side of the lock so that the bolt of the lock cooperates 
directly with the fixed keeper of a door casing, the knob serving as 
handle for opening the door. In this case, the means for unlocking the 
bolt in the retracted position, for example a pusher, are adapted for 
cooperating with the fixed keeper. 
The above described lock operates satisfactorily. However, it may be 
discovered that after opening the lock, the traction hook 90 can only be 
withdrawn from the main drive disk 130 if the user has previously released 
knob 210. FIG. 11, showing a lock modification including all the elements 
of the first lock, and in which the unchanged elements bear the same 
references as in the first lock, illustrates the state of the lock after 
opening but before the user has released knob 210 (figure 1b). 
In this situation, the traction hook 90 is held prisoner in notch 1410 of 
the main drive disk 1300. Thus, although the disengagement finger 94 bears 
on the traction hook 90, it cannot cause it to pivot in an anti-clockwise 
direction. This is what allows the user to prevent the automatic extension 
of bolt 70 during closure of the door and thus prevent closure of the lock 
and scrambling of the combination disks. 
The lock shown in FIGS. 11 and 12 is adapted for forcing the user to 
release the knob 210 before the door can be opened. The main drive disk 
1300 comprises, like that 130 of the preceding lock, two disks applied 
side by side 1400, 1500 and it differs therefrom in that its disk 1400 
comprises a second V shaped notch 1420, defined by two faces 1421, 1422. 
An auxiliary bolt 700 is provided in the form of a T comprising a leg 701 
and two arms 702, 703, one cf which 703 is extended by a finger 704 of 
smaller width, rounded at its end. 
The auxiliary bolt 700 is mounted in the lock, against the face of bolt 70 
turned outwardlY of the lock. Its arm 702 passes through an aperture 800 
formed in case 1000, below aperture 8. Its arm 703 is guided between the 
base of the traction hook 90 and post 15. Its leg 701, turned towards the 
sidewall of case 1000 extends between the sidewall 3 and the base of the 
traction hook 90. Thus, the auxiliary bolt 700 may slide in a direction 
parallel to the sliding direction of bolt 70. 
A helical spring 1600 is mounted on post 14 and comprises two legs 1601, 
1602 one of which bears on the sidewall 4 of case 1000 and the other on a 
side face of leg 701 of the auxiliary bolt 700, turned towards the 
sidewall 3 of case 1000, so that the auxiliary bolt is urged to a 
retracted position. Thus, finger 704 of the auxiliary bolt bears against 
the side face of disk 1400. In the situation shown in FIG. 11 where the 
user has not released knob 210 (figure 1b), finger 704 bears on the 
unnotched portion of the side surface of disk 1400, so that arm 702 of the 
auxiliary bolt 700 extends outwardly of case 1000 beyond bolt 70, until it 
passes through an aperture 2321 formed in keeper 2300, below aperture 2320 
intended to receive the bolt 70. Under these conditions, the user cannot 
open the door. 
On the contrary, in FIG. 12, the user has released knob 210 so that the 
traction hook 90 has come out of notch 1410 : the lock is in a condition 
similar to that shown in FIG. 3b. It is now notch 1420 of disk 1400 which 
faces the finger 704 of the auxiliary bolt 700. The auxiliary bolt 700 
thus released allows it to slide to a retracted position in which it bears 
against face 1422 of notch 1420 and where it no longer cooperates with 
keeper 2300 : the user can then open the door.