Cupboard for storing prepared meals, with cold-storage and reheating by microwaves

The invention relates to a cupboard for storing and bringing prepared meals to a suitable temperature, said cupboard being divided into a storage compartment or space and a compartment or chamber for bringing to suitable temperature. The meals are carried on trays superposed in the storage space. Individual metallic flaps comprising at least one mobile portion are provided at the level of each tray in order to separate or place the storage space and chamber in communication and transporting mechanisms are provided for transferring the dishes contained in inner compartments of the trays towards the chamber for bringing to suitable temperature and for returning them into the compartments where they were located after a sequence of bringing to suitable temperature in the chamber intended for this purpose. The invention finds particular application in the distribution of meals in collective catering.

BACKGROUND OF THE INVENTION 
The present invention relates to a cupboard for storing and taking to a 
suitable temperature prepared meals on individual trays with a view to 
distributing these meals some time after their preparation. 
SUMMARY OF THE PRIOR ART 
Such a storage cupboard may be used in all collective catering 
installations in which it is preferred to prepare the meals in advance 
rather than at the moment when they are to be consumed. This is 
particularly the case in hospitals, but many other cases may be envisaged, 
for example for catering in public transport (trains, planes, etc . . .) 
A certain number of problems are raised when a large number of complete 
meals (hors d'oeuvre entree, main dish, cheese, dessert, bread, drink, etc 
. . .) are to be prepared on the same tray, the meals differing from one 
tray to another as a function of the choice of the consumer or his diet, 
most of the contents of the tray having be kept cool at a temperature of 
about 7.degree. to 10.degree. C., the main dish being either in the form 
of a cold product to be eaten as such, or in the form of a chilled 
(+3.degree. C.) or frozen (-18.degree. C.) product to be consumed after 
having been reheated to a temperature of at least 65.degree. C. 
Each time a large number of meals are prepared with a view to being 
consumed at a meal time which is virtually the same for a certain number 
of consumers, the possible reheating of the chilled or frozen main dishes 
will have to be effected simultaneously for all the corresponding meal 
trays. 
There is then the problem of the risk of mixing the dishes of the various 
trays after they have been heated if the dish to be heated is removed from 
the rest of its tray (which, itself, must not cease to be kept at a cool 
temperature of about 7.degree. to 10.degree. C.) 
Another problem arises from the fact that it is sometimes necessary to take 
a group of trays to a suitable temperature with a view to immediate 
consumption, while other groups of trays stored in the same cupboard are 
to be heated later, with a view to later consumption. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to solve these problems and to 
allow complete meals to be prepared on individual trays, by rendering 
possible the preparation of meals in which the main dish is either in the 
form of a cold product or in the form of a chilled or frozen product, 
likewise rendering possible the transport and storage of these trays 
without separating the elements thereof, particularly during the possible 
reheating of the main dish while the other products on the tray are 
maintained at a cool temperature of 7.degree. to 10.degree. C. 
It is another purpose of the invention to provide that the trays are stored 
with maintenance of the temperature of the main dish at +3.degree. or 
-18.degree. C. if it is a chilled or frozen dish, and with maintenance of 
the temperature of all the other cold products at a cool temperature of 
7.degree. to 10.degree. C. 
Another purpose of the invention is to provide a cold-storage and reheating 
cupboard in which a certain number of trays may be stored which are to be 
heated at different times, without it being necessary to position the 
trays at determined spots or in a determined order corresponding to the 
time when they are to be subsequently heated. 
It is yet another object of the invention to prevent a tray which has 
already been reheated to from undergoing a second heating in case the tray 
is not withdrawn from the cupboard after its first heating. 
A further object of the invention is to assure that the main dish is kept 
hot after the reheating sequence, during the time when the trays remain 
stored in the cupboard before they are effectively distributed to the 
consumers. 
On the other hand, as certain meals may comprise cold, but not chilled or 
frozen dishes, or may even not comprise a main dish at all, another object 
of the present invention is to prevent the corresponding tray from being 
subjected to the action of refrigeration during the period of storage of 
the tray or from being subjected to the action of heat during the period 
of reheating.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
In FIG. 1, which very schematically shows a vertical section through the 
cold-storage and reheating cupboard according to the invention, the 
cupboard is essentially composed of two compartments, a compartment or 
space 10 for storage of the trays of prepared metals and a compartment or 
chamber 12 for reheating the dishes to be heated which are carried on the 
trays stored in the adjacent space 10. 
The storage space is arranged to receive one or more series of meal trays 
14 arranged on superposed runners 16. The trays may be introduced into the 
cupboard through a door (not shown) of the storage space. The trays are 
pushed on the runners 16 until they abut a separation wall 18 between the 
storage space and the reheating chamber. 
The separation wall 18 is pierced by openings 20, regularly spaced out over 
the whole wall, so that an opening 20 is located at the level of each tray 
which may be introduced into the cupboard. Each opening 20 is provided 
with a mobile closure flap 22 which may insulate or, on the contrary, 
place the storage space in communication with the reheating chamber at the 
level of each tray. The flaps 22 may be opened or closed by means of a 
control device 24 common to each series of vertically superposed flaps. 
The reheating chamber 12 is preferably a microwave chamber, i.e., it 
comprises a source of electromagnetic microwave rays, capable, by 
radiation, of strongly heating the bodies which absorb these rays and 
which are placed in the microwave chamber on the path of these rays. All 
of this reheating chamber 12 is insulated from the outside and from the 
storage space by metal walls, including the flaps 22 which must remain 
closed during the whole sequence of reheating by microwave radiation, so 
that the radiation remains confined inside chamber 12. 
The storage cupboard according to the invention comprises, in the reheating 
chamber, means for transferring through each opening 20 a dish to be 
reheated, carried by a tray 14 opposite this opening 20. These transfer 
means are constituted, as shown schematically in FIG. 1, by horizontal 
pallets 26 which may move in their plane on runners 28 opposite each 
opening 20 of the wall 18, so as to be able to penetrate from the 
reheating chamber towards the storage space when the corresponding flaps 
22 are open. During this displacement, each pallet collects the dish to be 
reheated, which is carried by the tray 14 and, on withdrawing into chamber 
12, each pallet takes the corresponding dish into this chamber with a view 
to proceeding with the reheating sequence. In the same way, once the 
sequence is terminated, the pallets 26 return the heated dishes onto the 
trays 14. 
The transfer means as well as their functioning will be described in 
greater detail hereinafter. It can be seen that the prepared meals are 
stored and reheated without real separation of the different constituents 
of the tray, since each dish to be reheated remains permanently opposite 
the tray which carried it; there is no possible mixing or inversion of the 
dishes of the different trays. 
To render FIG. 1, which is only a schematic view, more clear, some elements 
have been omitted. For example, only three runners 16 have been shown in 
the storage space 10, and only one runner carries a tray 14. Only two 
flaps 22 have been shown, and these moveover, have not been shown opposite 
runners 16 to facilitate the illustration, and only two transfer pallets 
26 have been shown. It is obviously to be understood that the trays are 
superposed over the whole height of the storage space and possibly, as may 
be seen from FIG. 2, in several stacks placed side by side, and that 
consequently the openings 20, flaps 22 and pallets 26 likewise extend over 
the whole height of the reheating chamber, as an opening 20, a flap 22 and 
a transfer pallet 26 correspond to each tray position. 
In the same way, FIG. 2 shows a simplified plan view of the interior of the 
cold-storage and reheating cupboard of FIG. 1. In this view, the storage 
space 10 is seen to comprise three stacks of superposed trays. Each tray 
is carried on runners 16 and is located opposite an opening 20 in the 
separating wall 18 between the two compartments. Opposite each tray 
position and in the microwave chamber 12 there is placed a pallet 26 for 
transporting the dish to be reheated. This pallet 26 may move in the 
direction of double arrow 30 due to the guide runners 28 which support it 
and due to a drive rod 32 which is moved in rotation by a drive shaft 34 
common to a whole series of superposed pallets. 
A system 24 for controlling the lifting and lowering of the flaps 22 is 
provided for each series of superposed flaps 22. One of them has been 
shown schematically in part of FIG. 2. It is placed laterally with respect 
to the series of flaps 22 and acts on rollers of these flaps to effect 
lifting, the rollers extending laterally with respect to the flaps 22. 
The lateral position of the control systems 24 obviously is determined by 
the necessity of leaving free passage for all the pallets 26 towards the 
trays. 
FIG. 3 shows in greater detail a tray which is particularly adapted to use 
in the cold-storage and reheating cupboard of FIG. 1. This tray has the 
particularity of having a closed inner compartment opening on a lateral 
wall at the front of the tray. This compartment is adapted to receive the 
main course of the meal carried by the tray, i.e., most often a dish to be 
reheated. The other ingredients of the meal which are cold products or 
products which do not require reheating are carried in conventional manner 
on the top of the tray. In FIG. 3, the tray is designated by 14, the 
lateral compartment by 42, the opening of this compartment by 44, and the 
space reserved for the ingredients other than the dish to be reheated, by 
46; this space is at the rear of the tray if the direction of introduction 
of the tray into the cupboard is taken as reference. 
The tray further comprises a feature which is a fastening lug 48 at its 
lower rear part, on each side thereof. This lug serves, as will be seen 
hereinafter, for fastening the tray on the runners 16 to make it fast 
therewith. 
FIG. 4 shows in perspective a view of a runner 16 serving to support the 
trays 14 inside the storage compartment. In fact, the runners are arranged 
in a special way, since they are mobile and may move longitudinally 
between a front position to which they are normally returned by a spring 
50 and a rear position in which they may remain fastened due to a lug 52 
fixed on a wall 54 supporting the runner and to a retaining attachment 
which will be seen more clearly in FIGS. 5 to 8. The two runners 16 
carrying each tray 14 are symmetrical (only one is shown in FIG. 4); the 
are connected together by their front part so as to form a drawer capable 
of carrying a tray and of moving therewith once the tray is fitted on this 
drawer. 
This arrangement of the runners 16 for supporting the trays arises from the 
necessity of providing the possibility of chilling or not chilling the 
dish contained in the inner compartment 42 of the trays. 
With reference to FIGS. 1 and 2 describing the storage cupboard, no mention 
has yet been made, in order to simplify the description, of the chilling 
system which is provided to assure that the chilled or frozen products 
contained in compartment 42 of each tray are kept cold (at either 
3.degree. or -18.degree. C.). 
This system of refrigeration normally comprises shafts for the circulation 
of cold air in the vicinity of the wall 18 separating the compartments 10 
and 12, so as to be able to present fluid inlet and evacuation openings at 
the level of the compartment 42 of each tray installed on runners 16. The 
front parts of the drawers formed by these runners constitute seals which 
obstruct the respective openings of the cold air circulation shafts when 
the drawers are returned into front position by springs 50. On the 
contrary, if the drawers are fastened in rear position, the cold air 
openings are unobstructed. The sealing system at the front of the drawer 
is such that each cold air may be directly solely into the compartment of 
a tray mounted on this drawer but not elsewhere, and particularly not in 
the microwave chamber since said latter is insulated by the closed mobile 
flaps 22, and not in the rest of the storage space due to a passage formed 
by an assembly of rectangular walls 56 in which is engaged the front part 
of the drawer as well as the front part of the tray carried by such 
drawer. The sealing system 58 forms a seal both with the walls of this 
passage and with the tray, whatever the position of the drawer, tightness 
being effected, moreover, with the openings of the cold air circulation 
shafts, when the drawer is in front position. The openings in question 
open out inside the corridor formed by the walls 56. 
The sealing system 58 is formed by a rectangular band leaving at its centre 
a free space corresponding to the dimensions of the opening 44 of the 
inner compartment of the trays so that the sealing band does not obstruct 
this opening and allows free passage not only for the cold air but also 
for the dishes which must be transferred by the pallets 26 from inside the 
compartment towards the microwave chamber. 
On the tray side, the sealing band must be closely adapted to this latter 
in order not to allow air to escape through the edges of the tray to 
outside the corridor 56. It is therefore necessary to provide a system of 
engagement of the tray on the runners 16 so that the tray remains closely 
applied against the sealing band of the drawer once it is positioned on 
this drawer. A hook 60 cooperates to this end with the rear lugs 48 of the 
trays 14. When these lugs are engaged in the hooks 60, the tray comes into 
close contact with the sealing band 58. Moreover, a supplementary purpose 
for these hooks is that they allow the tray-drawer assembly to be pulled, 
by acting only on the tray itself when its rear part is engaged in the 
hooks 60. This pull makes it possible to place the tray-drawer assembly in 
rear position, thus uncovering the openings for circulation of cold air, 
hitherto closed by the sealing system 58. On the contrary, in the absence 
of a tray, or if the tray is not engaged in the hooks 60, the withdrawal 
of the drawer into rear position is not possible and the openings of the 
cold air circulation shafts remain permanently obstructed by the drawer in 
front position. 
This particular arrangement is used not only for eliminating any leakage of 
cold air towards the storage space but also for preventing a meal, the 
main dish of which in the form of a cold product, being subjected to the 
action of the aif of the cold air circulation shafts at +3 or -18.degree. 
C. In fact, the trays which carry such cold dishes in their compartment 42 
are prevented from engaging in the hooks 60. 
By way of example, the following means are used for preventing this 
engagement: The trays are provided with a lid and a special lid is 
provided for the trays carrying a cold dish, this lid cooperating with a 
fixed stop 62 on the wall 54 to prevent the complete penetration of the 
tray in the drawer and in particular to prevent the hooking of the lugs 48 
in the hooks 60. 
The engagement of the tray not being possible, a pull of the tray to the 
rear is not transmitted towards the whole of the drawer, and said latter 
therefore remains in front position where the openings of the cold air 
circulation shafts remain obstructed by the seal system 58. Therefore no 
air leakage towards the storage space takes place. 
FIGS. 5 to 10 show how the seal system 58 is divided into two parts, a 
front part serving precisely to obstruct the cold air inlet and evacuation 
openings and a rear part serving both as seal with the edges of the tray 
around the compartment 42 and with the walls of the rectangular passage 56 
so as to confine the cold air inside the compartment 42 and inside the 
passage 56 when the drawer is in rear position, preventing any leakage 
towards the rest of the storage space. 
FIGS. 5 and 6 respectively show in lateral section and in plan view a 
mobile drawer assembly supporting a tray, this drawer being placed in rear 
position, which is possible only if a tray (shown in broken lines) is 
completely engaged by its rear lugs 48 in the hooks 60 of the runners 16. 
The runners 16 are retained in rear position, as already explained, by 
means of retaining attachments 53 cooperating with a lug 55 in the runner 
and a lug 52 fixed on the wall 54 supporting the runner 16. The 
longitudinal movement of the runner is made possible by guide grooves 59 
which cooperate with at least two lugs such as 52 on the wall 54. 
In rear position, the return spring 50 of the runner is stretched. 
The two runners 16 corresponding to a given tray position are connected and 
made fast with each other by a front metallic part 61 cut out at the level 
of the opening of the compartment of a tray engaged on the runners to 
allow free passage towards the compartment of the tray. The front metal 
part carries the seal system 58 which comprises a rectangular seal 63 
adapted closely inside the rectangular passage 56 and slidable inside this 
passage without leaving it both when the drawer is in front position and 
when it is in rear position. As has been explained, the part of the seal 
63 facing the front part of the tray 14 must be adapted to this front part 
so as to form a seal all around the compartment 42 of the tray. 
Consequently, as shown in the drawings, in the case of the tray 14 
comprising a notch at its front part, a seal part 65 is provided, forming 
a projection with respect to the rest of the seal 63 to fill the notch the 
tray. The seals 63, 65 present a certain elasticity and are compressed by 
the tray when said latter is engaged in the runners by its rear lugs 48. 
Right at its front part, the seal system 58 further comprises two other 
plates forming seals 67 and 69 which are adapted to obturate the openings 
of the cold air circulation shafts when the tray is in its advanced 
position (FIGS. 7 and 8). 
For each stack of superposed trays, a cold air inlet shaft 70 and a cold 
air evacuation shaft 72 have been provided laterally, each extending from 
one side of the stack of superposed trays. The shaft 70 opens into the 
passage 56 through a cold air inlet opening 74 against which the seal part 
69 may be applied. In the same way, the shaft 72 opens out through a cold 
air evacuation opening 76 against which the seal part 67 may be applied, 
to obstruct it. 
In the rear position of the mobile drawer carrying the tray 14, the 
compartment 42 of the tray is located opposite an opening 20 in the wall 
18 separating the storage space from the microwave chamber, and this 
opening 20 is closed by a metallic flap 22. 
A seal 78 is provided on the periphery of the opening 20 to avoid any 
leakage of cold air between the passage 56 and the microwave chamber 
through the not completely contiguous metal edges of the flap 22 and the 
opening 20. The flap 22 is applied against the seal 78 when it is in 
closed position. 
A perfectly tight enclosure is thus produced for keeping the dishes 
contained in the compartment 42 cold. 
As has already been explained, if a cold dish is contained in the 
compartment 42, it is provided with a special lid preventing the tray from 
engaging on the drawer and consequently preventing the drawer from being 
withdrawn in rear position, as the only means of gripping the drawer is 
the edge of a tray engaged on this drawer. There is therefore no chilling 
of the cold products. 
FIGS. 7 and 8 show a section and plan view similar to those of FIGS. 5 and 
6, but here the drawers are shown in advanced position, the plates 67 and 
69 obstructing the opening 76 and 74 of the cold air circulation shafts. 
FIGS. 7 and 8 show a supplemetary piece carried by the front part 61 of the 
drawer, the purpose of this piece being to allow the opening of the flap 
22 corresponding to this drawer solely when a tray is engaged on the 
drawer and when the drawer is in its front position. 
This piece is constituted by a spring 80 which is mounted on the part 61 
and a stop 82 fast with this spring and projecting on the side of the tray 
with respect to the part 61 so that the tray engaged the drawer may abut 
on the stop 82 and push the spring towards the rear of the housing 56, 
i.e. towards the flap 22. 
The spring 80--stop 82 assembly is mounted laterally with respect to the 
compartment 42 of the trays mounted on the drawer. 
In the absence of a tray on the drawer, the spring 80 is not pushed against 
the flap 22, whether the drawer is in front position or in rear position. 
In any case, whether or not a tray is engaged on the drawer, the spring 80 
does not abut on the flap 22 if this drawer is i rear position. The only 
case of the spring 80 abutting the flap 22 is the case of the drawer being 
in front position and a tray being engaged correctly on this drawer, at 
the same time. 
The whole of the front part of the drawer is more clearly visible in FIGS. 
9 and 10 which show enlarged detailed views of FIGS. 7 and 8, 
respectively. 
In particular, it is seen how the front part 84 of one side of the tray 
abuts the stop 82 to push the spring 80 against the flap 22. 
In the absence of a tray, the spring 80 is returned rearwardly by its 
elasticity and no longer abuts the flap 22 even when the drawer is in 
advanced position. 
The particular structure of the flaps 22 and their functioning may also be 
understood from FIGS. 9 and 10. 
Each flap is pivotally mounted about a fixed pin located at its upper part 
so that simply the weight of the flaps tends to return them normally into 
closed position. The pin, designated by reference 86, is fixed in a block 
88, preferably made of aluminum, forming a crosspiece between the various 
superposed flaps and constituting a portion of the wall separating the 
storage space and the microwave chamber of the cupboard. 
Each flap laterally carries a lifting roller 90 (FIG. 10), adapted to 
cooperate with a lifting system 24 already mentioned with reference to 
FIG. 2. 
This lifting system is constituted by a plate 92 extending vertically along 
the whole of a column of superposed flaps 22. the whole of the lifting 
system 24 is located laterally with respect to the opening 20 closed by 
the flap 22, so as not to hinder passage of the dishes to be reheated 
towards the microwave chamber 12. 
This plate 92 comprises a series of notches 94 distributed over its length 
with the same pitch as the superposed trays. These notches 94 are arranged 
to be able to receive the rollers 90. 
The plate 92 blocks the flaps 22 in closed position by their rollers 90 
when the notches 94 are not opposite the rollers. When the plate 92 is 
lifted with a view to opening the flaps, the notches 94 arrive at a 
certain point opposite the rollers 90. At this moment, either the spring 
80 abuts the flap 22 to try to open it and the roller 90 then penetrates 
into the corresponding notch 94, the continuing lift of the plate 92 then 
naturally taking along the flap 22 in its rise until the flap is 
completely opened, or the spring 80 does not abut on the flap 22 and said 
latter remains in closed position despite the lifting of the plate 92. 
Consequently, each lifting system 24 lifts the flaps of the same column 
simultaneously, but to the exclusion of the flaps corresponding to the 
positions of trays for which either no tray is engaged on the 
corresponding drawer or the drawer is in rear position. 
The flaps 22 are metal flaps of which the structure is particularly adapted 
to their function of insulation against the microwave radiation between 
the reheating chamber 12 and the tray storage space 10. 
A problem is raised as the separation wall 18 is made of metal and the 
flaps 22 are themselves metallic. If it is not desired to make a very 
tight adjustment of the flaps 22 in the openings 20, which would present a 
drawback due to the metal against metal friction which would adversely 
affect the action of the spring 80, it is necessary to provide a slight 
clearance between the periphery of the flap 22 and the opening 20. Now, if 
this clearance is small, there is the risk of arcs apparing between the 
opposite metal surfaces, when microwaves are emitted in chamber 12. There 
are therefore contradictory imperatives to avoid both the friction due to 
the rubbing of metal against metal if the clearance is virtually zero, the 
appearance of arcs due to the microwaves if the clearance is small, and 
the absence of tightness with respect to the microwaves if the clearance 
is large. 
To solve this problem, the flap 22 comprises on its periphery a system 
forming a wave trap over the whole of the part where it comes into contact 
with the edges of the opening 20 of the separation wall 18. 
This wave trap is constituted by a cavity 96 surrounding the flap part 22 
engaging in the opening 20, the cavity presenting a slot 98 opening 
towards the outside all around this part, and more specifically opening 
into the gap between the walls opposite the flap 22 and the opening 20 
when the flap 22 is closed. 
The cavity is a resonant cavity for the microwaves, and its dimensions are 
chosen as a function of the wave length used, so that there is effectively 
resonance. This resonance constitutes the essential property of the 
cavity, which enables it to function as a wave trap by recovering all the 
radiation which may infiltrate in the clearance left between the opening 
20 and the flap 22 and preventing any passage of rays towards the storage 
space. 
To make this flap forming a wave trap, a block of aluminum is provided, in 
which is machined a peripheral groove to the chosen dimensions. This 
groove is closed by a metal plate 100 for forming both the closed cavity 
96 and the slot 98 which runs along this cavity. 
Thus, mobile metal flaps are produced, having a very good tightness with 
respect to microwaves despite the considerable clearance which is left 
between the flap and the opening to facilitate the movement of the flap. 
The functioning of the storage and heating cupboard according to the 
invention will now be described, the functioning of the mechanisms for 
transporting the dishes to be reheated from the tray towards the microwave 
chamber and back again being more particularly described with reference to 
FIGS. 11 to 19. 
At the beginning, the storage cupboard is empty, the drawers for supporting 
superposed trays are all returned to rest position, i.e., front position, 
by their springs 50. The openings of the cold air circulation shafts are 
therefore all closed. 
As the drawers do not carry trays, the springs 80 do not exert any pressure 
on the metallic flaps separating the microwave chamber and the storage 
space at the level of each tray. 
These flaps 22 are, moreover, locked by plate 92 which maintains them in 
closed position. 
The transfer pallets 26 are in rear position, i.e., completely inside the 
microwave chamber 12. 
If the cold air chilling circuit is not yet in operation, it is switched 
on. The cold air is preferably produced by a unit with a ventilation 
system for producing suction in shafts 72 and delivery in shafts 70. 
By-pass systems are provided in order not to interrupt the chilling circuit 
when all the orifices are obstructed at the level of the trays by the 
drawers in front position. A by-pass flap is preferably provided which 
closes progressively as a function of the uncovering of openings 74 and 76 
at the level of the various trays, so that the flow of air remains 
constant at the level of the production unit. 
The chilling circuit being switched on, the trays are introduced through 
the doors of the cupboard, i.e., they are slid one after the other on the 
individual drawers, the opening of the lateral compartment being directed 
towards the rear of the storage space. 
The trays are introduced with their lids and it is recalled that a 
different lid being provided according to whether or not the main dish of 
the tray is a dish to be reheated. If the dish is not to be reheated, a 
lid is placed on the tray which prevents the complete engagement of the 
tray on the drawer. 
In the general case of the dish having to be reheated, the tray is 
completely pushed on the drawer until its rear part engages in the notches 
provided at this end in the runners 16. 
For trays which are engaged completely in the runners of the mobile 
drawers, it becomes possible to exert a rearward pull on the tray, taking 
the tray-drawer assembly over a distance of about 30 millimeters to a rear 
position where the drawer is hooked. 
This results in disengaging the drawer which obstructed the openings in the 
cold air circulation shafts and in switching on a system for chilling the 
compartment of the trays which were therefore able to be pulled 
rearwardly. 
It is provided that only dishes chilled at +3.degree. C. (in addition to 
the possible cold products) are arranged in the same cupboard, for a given 
type of cupboard, or only frozen dishes at -18.degree. C. (or possibly 
cold products) for another type of cupboard. 
In fact the refrigerator unit of a cupboard delivers only one type of cold 
air, either at about 0.degree. C. (chilled distribution) or at -35.degree. 
C. (quick-freeze distribution). 
For the trays which cannot be engaged in the runners, the impossibility of 
pulling the tray rearwardly causes the cold air inlet openings to remain 
obstructed. 
During this tray loading operation, the flaps 22 for insulating against 
microwaves are always locked by the ramps 92. 
The cupboard may thus function possibly for several hours between the 
moment of preparation of the meals and the moment of distribution thereof, 
with a correct refrigeration for the main dishes contained in the lateral 
compartments of the trays. 
A little before the distribution of the meals, a certain number of trays 
are selected, of which the main dishes will be reheated simultaneously. 
To this end, all the drawers carrying the selected trays are replaced into 
front position, leaving the others in rear position, without investigating 
whether the tray replaced in front position carries a cold dish or a dish 
to be reheated since, as has already been explained, the flap 
communicating with the microwave chamber will open only for the trays 
which are completely engaged on their drawer. 
During this procedure for placing the drawers of the selected trays in 
front position, a counting system may be provided for noting the number of 
selected trays in order subsequently to verify that all the selected 
plates have been withdrawn, to aviod reheating a dish of the same tray 
several successive times. 
To this end, it may be provided that the lug of a tray of which the drawer 
is replaced in front position meets a stop controlling a counting shaft 
common to all the trays of a column, the rotation of this shaft provoking 
a pulse on electrical counting means. 
A corresponding count-down will be effected when the dishes are withdrawn 
after the reheating sequence, to verify that all the selected trays are 
withdrawn. 
At the end of forward stroke of the drawer carrying a selected tray, this 
drawer re-obstructs the cold air orifices. Its spring 80 is pushed against 
the flap 22 which remains provisionally locked by the plate 92 for lifting 
the flaps, which plate is for the moment in low position. 
At the end of selection of the trays to be reheated, the doors of the 
storage space of the cupboard are closed and an automatic sequence for 
bringing to suitable temperature is controlled, which is effected in 
several stages, as follows: 
(a) A motor for controlling the plate 92 lifting the flaps 22 acts on said 
plate to lift it. Those flaps which are subjected to the pressure of the 
springs 80 will pivot on their pin and will be lifted via roller 90, by 
engagement of the latter in the notches 94 of the plate 92. The flaps 
corresponding to the trays for which a dish is to be reheated will 
therefore all be lifted when the plate 92 reaches an elevated position. 
(b) After the mobile flaps are lifted, the drive shafts 34 of the rods 32 
controlling the displacement of the transfer pallets 26 are rotated The 
pallets are driven towards the compartments of the trays and penetrate 
inside the compartments for which the flaps 22 are lifted. As will be 
explained hereinafter, a disconnecting system is provided to prevent a 
complete drive of the pallets located opposite closed flaps. 
The pallets 26 penetrate into the compartments beneath the dishes which are 
to be reheated and, in a return movement towards the microwave chamber, 
take these dishes into said chamber 12. 
(c) Once all the dishes to be reheated are placed on the pallets inside the 
microwave chamber 12, the lifting plate 92 is lowered so as to return 
flaps 22 into closed position to assure tightness against the microwaves 
between the microwave chamber 12 and the tray storage space 10. 
(d) The emission of microwaves is then initiated with a view to reheating 
all the dishes contained in the chamber 12. Of course, this latter is 
hermetically closed and its metal walls confine the microwaves inside the 
chamber, by reflexion. 
Certain parts of the objects contained in chamber 12, and especially the 
pallets 26, are preferably constituted by a material permeable to 
microwaves in order not only that they are not subjected to heating by 
these waves, but also that they do not prevent the reheating of the dishes 
which are to be reheated. 
For example, the pallets are made of the synthetic material which may be a 
complex of silicon stabilized with glass fibres. 
The microwaves emitted are for example waves at 2450 Megahertz produced by 
magnetrons. A variable duration of microwave emission may preferably be 
provided, as a function of the number of trays selected in each reheating 
sequence. For example, this duration is automatically established by using 
the data delivered by the system for counting the selected trays, 
mentioned hereinabove. 
(e) After the end of the microwave emission, the metal flaps 22 are again 
lifted automatically by the lifting system 24, in the same way as in stage 
(a). 
The same flaps as before are lifted since the positions of drawers and of 
trays on the drawers have not varied and the springs 80 always act on the 
same flaps. 
(f) The pallets 26 for transferring the reheated dishes are again displaced 
by the rods 32 fast with the common drive shafts 34, thereby to return the 
reheated dishes to inside the compartments of the trays 14. 
(g) Flaps 22 is then relowered, but only down to an intermediate position 
where the flaps partially close the openings 20, sufficiently to prevent 
the dish returned into the compartment from leaving. The flaps are 
immobilised by plates 92. 
(h) Movement of the transfer pallets 26 terminates with their return from 
inside the compartment to their rear position in the microwave chamber. 
The reheated dishes returned to the compartment remain therein, blocked by 
the flaps. 
(i) System 24 for lifting the flaps is controlled again to return, the 
flaps to completely closed position, locked by the plates 92. 
It may advantageously be provided that the operations from the lifting of 
the flaps with a view to reintroduction of the reheated dishes in the 
compartments of the trays, be controlled from a manual intervention for 
controlling unloading. It is then advantageous to provide that the 
products be maintained at suitable temperature by periodic microwave 
pulses between the end of the microwave emission for normal reheating and 
the manual intervention for controlling unloading. 
(j) The doors of the tray storage space are unlocked if automatic locking 
is provided after the trays are loaded. 
(k) The trays are unloaded manually with count-down, as explained 
hereinabove, to assure that all the heated trays have been unloaded. 
It is advantageously provided that the counting shaft is then locked in the 
direction of counting, so that it is impossible to engage new trays as 
long as the selected trays have not been unloaded, i.e., as long as the 
counting system has not been returned to its initial value. 
This operation constitutes the last stage of the reheating sequence and a 
new sequence may be effected for other trays which are possibly still 
stored in the cupboard. 
FIGS. 11 to 19 show schematic views representing operations (a) to (i) of 
the reheating sequence. 
In FIG. 11, the tray is shown in rear position, the spring 80 not abutting 
on the corresponding flap 22. 
Flaps 22 are in any case locked by the locking ramp 92. 
The transfer pallets 26 are placed in rear position inside the microwave 
chamber. 
In FIG. 12, the drawer carrying the tray 14 is moved to advanced position 
when said tray is selected. The tray shown in FIG. 12 is a tray which 
carries a dish to be reheated, the tray being completely engaged on the 
drawer and the spring 80 pushed by the tray, via the stop 82, abuts on the 
flap 22. 
FIG. 13 shows the operation of lifting of the flap by the plate 92, the 
roller 90 of the flap engaging in the corresponding notch 94 of the plate 
92 when said latter rises. 
When the flap 22 is conpletely lifted as shown in FIG. 14, the pallets 26 
are driven towards the inside of the compartments of the trays and slide 
beneath the dishes to be reheated, contained in said compartments. The 
pallet is then returned towards its initial position, taking the dish with 
it into the microwave chamber 12. 
FIG. 15 schematically shows the system with the dish to be reheated 
contained in the chamber 12 during microwave emission, i.e. after closure, 
due to plate 92, of the flaps 22 which were opened. 
FIG. 16 schematically indicates the means used for preventing the pallets 
from abutting against the flaps which remain closed (flaps of the non 
selected trays or flaps of the trays which carry cold products) while all 
the pallets 26 are driven simultaneously by a drive shaft 34 mentioned 
with reference to FIG. 2. 
A disconnecting ramp 102 is provided for each flap 22 which ramp covers it 
over its whole width so that when the flap is closed the ramp 102 is 
interposed between the pallet 26 and the corresponding flap 22. 
When the pallet is driven forwardly by its rod 32, its end meets the 
inclined disconnecting ramp 102 and is consequently lifted as seen in FIG. 
16, this lift being continued until the rod 32, still driven, separates 
from the pallet 26 and continues its stroke. The disconnected pallet 26 
slides downwardly along the ramp 102 until it returns to its initial 
position shown in dotted lines in FIG. 16. 
When the rod 32 returns rearwardly during the return movement of the 
assembly of pallets towards the microwave chamber, the rod 32 hooks on the 
pallet 26, which returns the assembly to its initial state. 
To render fastening and disconnecting of the rod 32 on and from pallet 26 
possible, the connection between the rod and the pallet is simply a notch 
104 provided at the lower part of the pallet, the rod leaving the notch 
when the pallet is lifted. As the pallet 26 is supported by runners, as 
has been explained with reference to FIG. 2, it naturally returns to the 
initial position and the rod 32 which moves in a fixed plane may reengage 
in the notch 104 on its return. 
The disconnecting ramp 102 is mounted to pivot so as to be able to be 
lifted by the flap 22 when said latter is lifted by its lifting system. In 
fact, the principle of the ramp 102 means that it completely obstructs the 
passage between the pallet and the flap when said latter is closed, and it 
is therefore necessary for this ramp 102 to disappear when the flap is 
open. 
As seen in FIGS. 13 and 14, the ramp 102 lifts at the same time as the 
flap. It is simply pushed by the latter and drops by its own weight at the 
same time as the flap. 
FIG. 17 shows the return stage of the transfer pallet 26 to inside the 
compartment of the tray 14 to return the dish once heated. This operation 
obviously takes place only after the end of the microwave emission and 
after lifting of the flaps 22 which were closed during this emission. 
FIG. 18 shows the withdrawal of pallet 26 towards the microwave chamber 12 
after partial reclosure only of flap 22 by the lifting plate 92. This 
reclosure is simply sufficient for the withdrawal of the pallet 26 without 
the reheated dish, which abuts against the partially closed flap. 
FIG. 19 shows the return into initial position, the pallet 26 having 
returned into the microwave chamber 12 and the flap 22 being again closed 
and locked by plate 92. 
The corresponding tray may be unloaded from the storage cupboard, the 
reheating sequence being terminated.