Lockable lock for drink distributing trolleys in aircraft

A lockable lock is disclosed, particularly for drink distribution trolleys in aircraft, comprising an additional latch (20) for locking the sliding bolt (7) whose movement is dependent on the pivoting movement of an operating and unlocking lever (8) which also displays, through the aperture (13), the provisioned state of the trolley, the lever (8) being actuated by a key fitted on its shaft (9).

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention, which relates more particularly to trolleys for distributing 
drinks in aircraft, concerns a lock which can be locked automatically. 
2. Description of the Prior Art 
Drinks, and particularly fresh drinks, are distributed in aircraft by means 
of small trolleys which are heat insulated and have a plurality of shelves 
or compartments for storing these drinks. These trolleys are pre-stocked 
on the ground before being brought to the aircraft. It is the commercial 
navigating staff who distribute drinks to passengers before storing the 
trolley or trolleys, at least partially emptied, in a particular zone of 
the aircraft, where they will then be recovered during a replenishing 
stop. They thus effect a distribution circuit before returning to the 
preparation center. 
During these multiple movements or handling by the navigating or non 
navigating staff, it is obviously necessary for these trolleys to be 
locked so as to avoid the theft of their contents. This is why, up to now 
these trolleys, whose inventory is made before each departure, are sealed 
with a certain color by the preparation center so as to show that they are 
fully provisioned. On board, the navigating staff, who have an appropriate 
tool, may unseal the trolley and distribute its contents. At the end of 
the service, the trolley must be re-sealed with another appropriate tool 
and marked to show that its contents have been depleted. That takes place, 
for example, by re-sealing with another color to thus show that it is 
incompletely provisioned. These operations occur on each flight until the 
end of the cycle when the trolleys are returned to the preparation center 
to be re-stocked. 
This procedure involves the purchase of a large number of seals and the 
provision of sealing and unsealing tools for the apparatus or the 
navigating staff. Furthermore, the particular marking of the provisioned 
state of each trolley involves painting the seals in question with 
different colors. 
It will be readily understood that such materials are expensive, but apart 
from this drawback, the sealing and unsealing operations are time-wasting 
and fastidious, whether at the preparation center or in flight for the 
navigating staff, without speaking of the risks of slight injuries (broken 
nails, injured fingers . . . ) caused by handling such tools. 
These drawbacks have led the Applicant to perfect an automatically lockable 
lock, which can be unlocked by means of a key, which also displays the 
provisioned state of the trolley and which can be readily fitted on the 
normal doors of said trolleys. 
SUMMARY OF THE INVENTION 
Therefore, an object of the present invention consists of a lockable lock, 
particularly for drink distributing trolleys in aircraft, comprising a 
control handle operating a sliding bolt by means of a crank link, which 
lock is equipped with a supplementary latch for locking the sliding bolt 
whose movement is dependent on the pivoting movement of an operating and 
unlocking lever, which also plays the role of device displaying the 
provisioned state of the trolley, said lever being movable by means of a 
key allowing it to be rotated in two directions, and/or a key allowing the 
pivoting operation only in one direction of rotation. 
The operating lever is attached to a pivoting shaft passing through an 
orifice of the door situated above the rotational shaft of the control 
handle of the sliding bolt, which pivoting shaft, through which a 
transverse pin passes, permits its rotation by means of keys. 
In addition, the operating lever is in the form of a right-angled bracket 
with two legs, one leg of which has at its end a colored disc on its face 
oriented towards the door, which may appear through a display aperture 
provided in the door above the shaft and another leg of which has at its 
end a profiled opening through which passes a small shaft which is movable 
in said opening. 
According to a particular characteristic of the invention, the latch 
extends vertically along the rear face of the door, between the operating 
lever with which it cooperates via the shaft passing through an aperture 
of said latch, and the sliding bolt. It is returned by a spring hooked on 
to a lug of the latch and a support plate of said latch. The lower part of 
the latch is in the form of an L whose flat end, as well as an adjacent 
rounded portion, are applied against the lower part of the cranked link of 
the sliding bolt. 
According to another characteristic of the invention, the barrel of a key 
ends in a double diametrical notch able to be engaged on the pin, on each 
side of the shaft. Furthermore, the barrel of another key ends in notches 
bordered on one side by inclined surfaces and on the other by straight 
portions parallel to the longitudinal axis of the key which act in a 
single direction on the pin. 
Other particular features, as well as the advantages of construction and 
operation of the lock according to the invention will be clear from the 
following description of one embodiment, with reference to the 
accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows a door lock of the prior art, showing the front visible and a 
plate of a door lock 1 of a trolley equipped with a folding handle 2 and a 
control handle 3 pivoting about a shaft 4 and able to occupy two positions 
C (closed) or O (open) marked on the front face of the door. In the closed 
position shown, handle 3 bears against a U shaped stop 5 able to serve for 
locking the handle in this position. At the level of its shaft 4, the 
handle is attached to a crank lever 6 for operating a sliding bolt 7 
which, according to its position, projects or not into a fixed keeper not 
shown of the trolley 101. It will be noted that link 6 and the sliding 
bolt 7 are located behind the front plate of lock 1, as can be seen in 
FIG. 2. In FIG. 2, the complementary and component parts of the lockable 
lock are shown, which are mounted on the rear face of lock 1, which cannot 
be seen. Primarily, an operating and unlocked lever 8 is attached to a 
pivoting shaft 9 passing through an orifice 10 of the door located in line 
with and at some distance above the shaft 4 of handle 3. At the level of 
this lever 8, a support plate 16, fixed on the rear face of the door, has 
passing therethrough a screw 17 for fixing the pivoting shaft 9, which 
holds lever 8 in position and allows it to rotate. Lever 8 is in the form 
of a right-angled bracket with two legs, an upper leg 11 of which has at 
its end a colored disc 12 on its face oriented towards the door plate, 
which disc may appear through a display aperture 13 itself located above 
shaft 9. The lower leg 14 of lever 8 has at its end a profiled opening 15 
in the form of an egg, through which a small shaft 18 passes, which is 
movable in opening 15 which itself passes through an elongate aperture 19 
provided in latch 20. This latch 20 extends vertically and may slide along 
the rear face of door 1 between the support plate 16 and a complementary 
guide blade 21, also fixed to the door, or between the operating lever 8 
and the sliding bolt 7. The latch has a particular shape with notably a 
lug 22 for hooking thereon a small return spring 23 fixed to the support 
plate 16. 
The lower part of latch 20 is in the form of an L whose flat end 24, as 
well as an adjacent rounded portion 25, are intended to be applied against 
the lower part of link 6, under conditions which will be explained further 
on. 
It will be understood that the assembly of these parts housed behind plate 
1, namely essentially the operating lever 3 and latch 20, are attached to 
each other in a particular way. Only a front portion of the pivoting shaft 
9 is apparent on the front of the door since it projects from orifice 10. 
It is this front portion of shaft 9 through which a transverse pin 26 
passes which may be rotated by means of two types of key. On the one hand, 
a key 27a, shown in FIG. 3, is used solely by the preparation center, 
whose hollow cylindrical barrel 28 ends in a double diametrical notch 29 
which may engage pin 26 on each side of shaft 9. This key 27a allows the 
user to operate it in both directions as shown by the arrow. On the other 
hand, a key 27b, shown in FIG. 4, is intended for the navigating staff, 
whose barrel 28 ends in notches 30 bordered on one side by inclined 
surfaces 31 and on the other by straight portions 32 parallel to the 
longitudinal axis of the key. The user can therefore rotate this key 27b 
only in one direction in which it is the straight portion 32 which bears 
against pin 26. 
The lock thus described operates in the following way. FIG. 5 illustrates 
the position of the different parts when door 1 is closed and the lock is 
locked. 
This represents the situation of the lock of a provisioned trolley leaving 
the preparation center. To place the parts in this position, shaft 9 has 
had to be rotated with key 27a to bring disc 12 in line with the display 
aperture 13. 
The control handle is then in a closed low position and thus, as usual, 
holds the sliding bolt 7 engaged in the fixed keeper via link 6. In this 
first situation, it can be seen that latch 20 is in a top position in 
which its lower flat end 24 is at the level of link 6 and consequently 
prevents sliding bolt 7 from returning inside door 1. There is thus 
locking of the sliding bolt and of the control handle. To this top 
position of latch 20 there corresponds--via shaft 18--a top position of 
leg 14 of the operating lever 8. Thus, the other leg 11 is substantially 
vertical and the colored disc 12 is in line with the display aperture 13. 
Thus, this color seen through said aperture indicates that the door is 
locked and that the provision of the trolley is complete. 
If the preparation center for any reason whatsoever desires to open the 
door of a trolley 101 thus locked, the key 27a is available. 
The trolley 101 thus locked which has been transferred to an aircraft, must 
be unlocked by the navigating staff by means of key 27b which they have 
available. They fit then the key on the pivoting shaft 9 and rotate it in 
the only direction possible in which the straight portions 32 may act on 
pin 26. In a first phase, lever 8 will turn, which firstly results in 
freeing laterally leg 11 of the lever and retracting the colored disc 12 
outside the display aperture 13, as can be seen in FIG. 6. Through this 
aperture a background on the back part of the door lock having a color 
other than the disc 12 can then be seen indicating unlocking. During this 
first phase of the rotational movement, the small shaft 18 has a relative 
bottom to top movement inside the profiled opening 15 during the downward 
movement of leg 14 of lever 8. During the second phase of the rotational 
movement, lowering of the lower leg 14 of lever 8 will act on latch 20, by 
the action of shaft 18 on the base of its aperture 19, and will then cause 
it to slide downwards in the guide blade 21, against the return force of 
spring 23. 
It can be seen in FIG. 7 that latch 20 escapes from link 6 and, thereafter, 
the navigating staff may operate handle 3 upwards and open the door. We 
then have the position illustrated in FIG. 8 in which, because of the 
rising movement of handle 3, link 6, which has effected a pivoting 
movement corresponding to the re-entry of sliding bolt 7 and opening of 
the lock, is positioned against the rounded portion 25 of latch 20. 
Thus, latch 20 is locked in the low position against link 6, which prevents 
the latch from returning upwards despite the fact that spring 23 is 
tensioned. Lever 8 can then not come back to its first position in which 
the colored disc 12 would re-appear in the display aperture 13. 
When the navigating staff has finished distribution, they close the door by 
lowering handle 3 which engages the sliding bolt 7 in the keeper. Under 
the action of spring 23, the latch 20, freed from link 6, rises to the 
automatic locked position of link 6 (FIG. 6). But lever 8 remains in the 
position shown in FIG. 6 in which the colored disc is not visible. That 
means that from the first unlocking effected by the navigating staff, the 
indication of the complete provisioned state can no longer be displayed by 
the colored disc 12. If the navigating staff, or the staff of another 
aircraft wishes to open the door again, they must use the key again for 
operating the latch. But in any case, because of the single direction of 
action of its key, it is not possible to replace lever 8 in the original 
position illustrated in FIG. 5, only the staff of the preparation center 
could do so with their key having a dual direction of rotation.