Holder for objects inside a rotating drum

A holder for objects inside a rotating drum, particularly that of a sterilizer. The holder includes a pressure plate which can be brought into position for holding the objects by a motor-driven mechanism. This mechanism has a rod with threaded portions interacting with sleeves. These sleeves control the movement of pairs of link arms which are rigidly fixed to the pressure plate and are in contact with the drum wall.

The present invention has for an object a device for holding objects inside 
a rotating drum. 
More precisely, the invention relates to a device for holding objects which 
are placed inside the rotating drum of apparatus such as sterilizers or 
the like. 
Sterilization of objects or of products in the food or pharmaceutical 
industry such as tins, jars, receptacles, bottles, etc., is often effected 
in so-called autoclaves in which the products to be treated are introduced 
then removed after the treatment has terminated. These products to be 
treated are disposed in baskets, stackable trays or like elements. For 
certain of these products, the heat treatment for sterilization must be 
effected by a rotating movement of the product inside its packing. This 
movement of rotation is produced by the rotation, within the autoclave, of 
a drum containing baskets filled with the products to be sterilized. The 
same type of problem is raised for draining or tipping certain products on 
an apparatus other than an autoclave which is in that case called drainer 
or tipper. This operation allows elimination of the water deposited on 
these products by gravity during sterilization. 
French Patent 86 02046 describes in detail an example of such a 
sterilization autoclave with rotating drum. 
During rotation of the drum, it is necessary to avoid any movement of the 
products which might cause them damage or break them, by immobilizing them 
inside the drum with the aid of a holding device. In general, the 
individual products are stacked in troughs or placed on trays and it is 
the assembly of these troughs or trays which must be held inside the drum. 
To maintain the objects in place inside a rotating drum, it has already 
been proposed, as in French Patent Application FR-A-2 605 226, to control 
trays for holding the objects with the aid of jacks acting perpendicularly 
to the holding plate. Such a solution indeed makes it possible to obtain 
holding of the objects inside the drum, without manual intervention, but 
it is not satisfactory insofar as the effective holding of the objects 
depends on the correct functioning of the jacks and the supply system 
thereof. In addition, the functioning of jacks in an environment which may 
be aggressive or at least at high temperature, is unreliable. 
It has also been proposed in U.S. Pat. No. 2,629,312 to ensure holding of 
objects inside a rotating drum with the aid of mechanisms for displacement 
of a pressure plate, this mechanism being actuated manually with the aid 
of a crank. This solution is hardly satisfactory insofar as the 
environment in which if must intervene is hostile and insofar as such 
manual interventions do not allow a chain for automatically treating the 
objects to be set up. 
In order to overcome the drawbacks mentioned above, an object of the 
invention is to provide a device for maintaining objects in a rotating 
drum, particularly a sterilizer or like apparatus, which makes it 
possible, on the one hand, to ensure an efficient pressing of the product 
or the baskets containing the products in automatic manner and which, in 
addition, ensures such clamping in reliable manner during the whole 
operation of heat treatment corresponding, for example, to the 
sterilization of the products. 
To attain this object, the device for holding objects in a rotating drum, 
according to the invention, is characterized in that it comprises at least 
one pressure plate presenting a substantially plane bearing face and means 
inside the drum for displacing the plate between a position of rest and a 
position of hold in which the bearing face of the plate is applied against 
the upper face of the objects to be held, the displacement means 
comprising: 
a rod mounted to rotate about its longitudinal axis and comprising n 
threaded portions, at least one portion having a direction of threading 
opposite that of the other threaded portion or portions; 
n tapped sleeves, each sleeve cooperating with one of the n threaded 
portions; 
n link arm systems, each system cooperating with one of the n sleeves and 
presenting one end articulated on said plate; 
a fluid motor coupled to the rod to provoke rotation thereof in two 
directions of rotation when the motor is supplied; and 
means for supplying the motor with fluid, the supply means traversing the 
end wall of the drum substantially along the axis of rotation thereof, 
whereby, in a first direction of rotation, the link arm systems bring said 
plate in its position of rest and, in a second direction of rotation, they 
bring said plate into position of hold. 
It will be understood that pressing and holding of the objects in place is 
obtained by the displacement of the plate, itself obtained automatically 
by controlling the fluid motor. In addition, it will be understood that 
hold is ensured by the screw-nut (sleeve) and link arm system which is 
substantially self-locking in position of hold, which means that, even in 
the case of failure of the fluid motor, the objects remain efficiently 
held in place. 
According to a first embodiment, each link arm system comprises a pair of 
assemblies forming link arms, each assembly of the same pair having a 
first end articulated on one of said sleeves and a second end articulated 
respectively on said plate and on a fixed element fast with said drum. 
According to a second embodiment, the device is characterized in that it 
comprises a number 2p (2p=n) of link arm systems, grouped in two's, each 
link arm system comprising a pair of assemblies forming link arms, each 
assembly of the same pair having a first end articulated on one of said 
sleeves and a second end articulated respectively on the second ends of 
the assemblies forming link arms of the pair belonging to the same group, 
and one of said second ends being in addition articulated on said plate.

Referring firstly to FIGS. 1 to 4, the assembly of the drum provided with 
its device for holding objects, according to a first embodiment, will be 
described. FIG. 1 shows the drum 10 constituted by a cylindrical lateral 
wall 12 whose axis XX' is at the same time the axis of rotation of drum 
10, and by a circular end wall 14 whose periphery is welded to the lateral 
wall 12. In its lower part, the drum is provided with a floor 16 on which 
are mounted rollers 18 to facilitate introduction of the baskets 20 in 
which the objects to be sterilized are placed. 
The holding device comprises a mobile plate 22 which may be displaced with 
the aid of a mechanism between a position of hold as shown in FIG. 2, in 
which the plate 22, or more precisely its lower face 24, is applied with 
pressure on the upper face 26 of the basket 20 and a position of rest 
shown in FIG. 1 in which the plate is moved away from the top 26 of the 
basket in order to allow introduction or removal thereof into or from the 
drum. 
The displacement device is constituted by a rod 30 which may be set in 
rotation about its longitudinal axis YY', axis YY' being parallel to the 
axis of rotation XX' of drum 10. Rod 30 comprises a plurality of threaded 
portions. In the case of FIG. 1, the rod comprises three threaded portions 
referenced 32, 34 and 36 respectively. On each threaded portion is mounted 
a tapped sleeve, the tapped sleeves being respectively referenced 38, 40 
and 42. On each side of the sleeves 38 to 42 are mounted half-shafts 
referenced 44 and 46 for the sleeve 42 shown in FIG. 4. These two 
half-shafts 44 and 46 are aligned. On each half-shaft 44, 46 is pivotally 
mounted a first end of two pairs of link arms respectively referenced 48, 
48' and 50, 50' for the sleeve 42. As shown in the Figures, a U-angle 52 
is fixed on the upper face 22' of the plate 22 and disposed in its 
longitudinal direction. Shafts such as 54 are engaged in orifices made in 
the sides of the angle 52. There are as many shafts as sleeves 38 to 42. 
In the same way, a U-angle 56 is fast with the top part of the lateral 
wall 12 of the drum. Shafts such as 58 are engaged in orifices made in the 
sides of the angle 56, the number of shafts 58 also being identical to the 
number of sleeves 38 to 42. The second ends of the upper link arms 48 and 
50 are engaged at the ends of the upper shafts 58 and the second ends of 
the lower link arms 48' and 50' are engaged at the ends of shafts such as 
54. It is seen that, in this way, three systems of link arms are 
reconstituted, which are, on the one hand, fast with the sleeves 38 to 42 
and, on the other hand, respectively fast with the angle 56 connected to 
the drum and the angle 52 connected to the plate 22. The associated 
threads and tappings of the threaded parts 32 and 34 are in a first 
direction, the thread of the threaded part 36 being, of course, in a 
second direction. 
It will thus be understood that, by rotating the rod 30 about its axis YY', 
the pairs of link arms will be spaced apart and the plate 22 lowered 
towards its position of hold and that, by rotating the rod in the opposite 
direction, the link arms are brought closer and the plate 22 is raised. 
The end 31 of rod 30 is coupled to the shaft 59 of a pneumatic motor 60 of 
a type known per se, via a system 61 of the Universal joint type. Motor 60 
is provided with a flange 62 which is fixed on a bracket 64 fast with the 
top part of the lateral wall 12 of the drum. 
It will be understood that, thanks to the presence of the Universal joint 
system 61, motor 60 transmits the torque to rod 30 in all the positions 
that the latter occupies during its rotation under the effect of the link 
arms 48, 48'. 
Instead of using a pneumatic motor, it would be possible to employ a 
hydraulic motor, on condition that a control liquid is chosen which is 
adapted to the temperature conditions prevailing inside the drum. 
Motor 60 is supplied via two conduits 70 and 72 to allow the two directions 
of rotation of the motor. The two conduits 70 and 72 are supplied with 
compressed air via two rotating joints which are more readily visible in 
FIG. 5, which will be described hereinafter. 
The end wall 14 of the drum 10 is fast with a shaft 74 for rotation 
disposed along axis XX' of the drum. Shaft 74 comprises an axial channel 
76 for the possible introduction of probes in the drum. Shaft 74 is 
mounted to rotate in a fixed bearing 78 via roller bearings 80 and 82. 
Shaft 74 is in addition pierced with two blind conduits 84 and 86. The 
blind end of each conduit is connected to radial pipes respectively 
referenced 88 and 90. The pipes 88 and 90 open out in the outer wall 92 of 
the shaft 74. Opposite the pipe 88, the inner wall 94 of the bearing 78 is 
provided with a circular groove 96 itself connected to a radial supply 
pipe 98 made in the fixed bearing 78. Symmetrically, opposite pipe 90, the 
inner wall 94 of the bearing 78 is provided with a circular groove 100 
connected to a second supply pipe 102. 0-rings 104, 106, 108, 110 are 
mounted on either side of the annular grooves 96 and 100. As shown in FIG. 
5, the open end of the pipes 84 and 86 is connected to the ends of pipes 
70 and 72. In this way, by this double rotary joint system, the motor 60 
may be permanently supplied either with the compressed air applied to the 
fixed pipe 102, or with the compressed air applied to fixed pipe 98. 
If reference is again made to FIGS. 1 and 2, it is seen that the second end 
33 of the rod 30 may be connected, via a Universal joint system 104, to a 
manual rotation-imparting member 106 constituted for example by a crank. 
In this case, even in the event of failure of the motor 60, it is possible 
to control rotation of the rod and therefore the movements of the plate 
22, manually. 
FIG. 3 shows the drum 10 mounted in the autoclave enclosure of a 
sterilizer. This FIG. shows the outer envelope 110 of the sterilization 
with its "floor" 112 on which are mounted two support rollers 114 and 116 
mounted idly to guide the lateral wall 12 of the drum 10 during its 
rotation. FIG. 3 also shows the baskets 20 containing the products to be 
sterilized, the presser plate 22 and, in symbolic form, the device 120 for 
displacement of the plate 22. 
FIG. 6 shows, in simplified form, a second embodiment of the means for 
displacing the plate 22. The rod 30' comprises four threaded portions 130, 
132, 134 and 136 with alternately reversed pitches. On the threaded 
portions are mounted four sleeves 138, 140, 142 and 144. On each sleeve 
are articulated the first ends of two link arms, 146 and 148 for sleeve 
138 and 150 and 152 for sleeve 140. The second ends of the link arms 148 
and 150 are articulated on each other and on the "shoe" 154. 
Symmetrically, the second ends of the link arms 148 and 152 are 
articulated on each other and on the angle 56 fast with the plate 22. The 
link arms 156 to 162 associated with the sleeves 142 and 144 are mounted 
in the same way. Two deformable parallelograms are thus constituted whose 
configuration is controlled by the relative position of the groups of 
sleeves 130, 132 and 134, 136. 
The end 31' of the rod 30' is directly fast with the end of the shaft 59 of 
the pneumatic motor 60. The latter is fixed on the bracket 64 via the 
flange 62. It will be understood that, by controlling the motor 60 in a 
first direction, the apices of the parallelograms bearing the shoes 154 
and the plate 22 move apart mutually until the shoes 154 come into contact 
with the top part of the lateral wall 12 of the drum, and that, 
simultaneously, the plate 22 is applied against the upper face of the 
baskets 20. The baskets are then held perfectly. By controlling the 
rotation of the motor 60 in the other direction, the shoes 154 and the 
plate 22 are moved closer towards the rod 30', which releases the baskets 
20. 
It will be understood that this second embodiment presents the same 
advantages as the first embodiment. An additional advantage resides in the 
fact that the rod 30' is immobilized in translation, which makes it 
possible to mount its ends in two bearings 160 and 162 fast with the drum 
10. On the other hand, it is necessary to effect a very precise 
positioning of the rod 30' for the shoes 154 to come into abutment against 
the wall 12 at the same time as plate 22 comes into contact with the upper 
face of the baskets 20. This implies that this second embodiment is very 
well adapted to the case of the objects loaded in the rotary drum always 
presenting the same height. On the contrary, in the case of the first 
embodiment, the holding device is adapted to different heights of objects. 
In the foregoing description, only the case of the holding device 
comprising one sole pressure plate has been considered. It goes without 
saying that the invention would not be exceeded if the rod 30 or 30' 
served to control several separate pressure plates, via link arm systems.