Machine for producing complex objects by multidirectional deposition of thread

The invention concerns the production of three-dimensional thread packages. Vertical rods (11) are maintained in a stationary arranged network by engagement through perforated plates (12,13). A thread (10) is deposited from above this network by a shuttle (9) in a sinuous path between upper end portions of the rods (11). The layers of thread thus formed in succession, supported by the perforated plate (12) which undergoes a descending movement, are compacted by a perforated plate (7) which is lowered upon the finishing of each layer. A lacing arrangement (35) replaces the rods (11) by threads after the thread laying phase.

FIELD AND BACKGROUND OF THE INVENTION 
This invention concerns a process and a machine for the production of a 
package made up of threads assembled by multidirectional weaving i.e. 
deposit of thread about a network of rods; and susceptible to serve as a 
framework in the manufacture of a body made of composite material. 
Such frameworks are utilized, after impregnation with a suitable binder and 
subsequent hardening of the binder, for the purpose of obtaining 
components capable of withstanding very high mechanical and thermal 
stresses, for example, those used for the structural components of 
satellites, re-entry bodies, or rotor hubs for rotary winged aircraft. 
A manual process is already known from U.S. Pat. No. 4,218,276 (AVCO), for 
creating three-dimensional structures, consisting of upwardly pointed 
vertical and parallel needles, held apart by two reeds arranged at right 
angles. Over the needle points a layer of fabric is then placed, and 
against it is pressed a plate equipped with holes corresponding to the 
needles, the points of which penetrate the fabric which is pressed 
downwardly by the plate. This operation is repeated by rotating the reeds 
until the required stack thickness is obtained, after which the stack is 
removed from the machine. Then, filamentary reinforcements are introduced 
into the holes made in the stack so as to form a three-dimensional 
structure. In order to put this process into operation, it is therefore 
necessary to have available layers of fabric manufactured in advance and 
trimmed to the dimensions required for each specific product. Moreover, 
while this U.S. patent proposes the creation of so-called 
three-dimensional structures in which rigid components such as metallic 
needles are arranged vertically, it can be seen that such structures 
cannot be obtained by the simultaneous deposit of threads on those 
needles. Instead, bonded layers are formed first, after which they are 
stacked up and then penetrated by the needles. 
Likewise known, from U.S. Pat. No. 4,183,232, to the present applicant, is 
a three-dimensional weaving machine for the production of hollow, rotating 
woven frames. Into a network of rods, held parallel to the generating 
lines of the body to be created by means of gratings, there are introduced 
and woven on a fixed plane, on the one hand, circumferential threads by 
unwinding in concentric circles parallel threads, and on the other, radial 
threads by knitting by means of a needle, of a thread in the form of a 
chain. In this process, the rods can be metal pins which, at the end of 
the weaving, are removed and replaced, through a lacing arrangement, by 
threads which provide longitudinal filling. 
The process known from U.S. Pat. No. 3,955,602 makes it possible to create 
pieces of simple geometric shape, such as, essentially, parallelepiped 
blocks in which the threads deposited on a single plane emerge on either 
side of a network of vertical pins with an overlap, requiring, on this 
account, the use of a thread locking device. U.S. Pat. Nos. 3,955,602; 
4,183,232 and 4,218,276 discussed above are incorporated here by 
reference. 
In general, the processes according to the prior art require specific 
tooling for the piece to be made to the extent that the weaving is linked 
to the separation or pitch of the vertical pins. Consequently, they do not 
permit rapid and economical changes in the woven pieces. 
Moreover, most of the known processes for the creation of woven pieces of 
three dimensions require the installation of a substantial number of 
thread bobbins, and consequently, the manipulation of same in order to 
pass from one piece to another. 
Finally, the essential problem to be resolved in the weaving of structures 
of the type considered lies in the fact that the threads to be introduced 
in a network of pins or rods must be deposited in such a way that no 
residual tension will be retained in them. 
In fact, the accumulated tensions would finally deform the network and 
prevent continued production, by shutting down the respective machine, for 
example. This problem is usually resolved, either empirically, through the 
skill of the operator, or by the use of pin-holding equipment with 
introduction of the threads under tension and threading each thread into a 
needle. 
SUMMARY OF THE INVENTION 
The present invention makes it possible to remedy the disadvantages of the 
processes and equipment of the prior art. Its objective is a process which 
consists, in an initial phase of production, of creating a network of 
rigid rods, parallel but not joined together, of depositing at one end of 
said stationary network a single thread following a twisting route 
zigzagging between the terminal portions of the rods, with the thread 
forming successive layers superimposed on each other on planes transverse 
to the direction of the rods, of compressing these layers of thread as 
they are formed, this compression being accompanied by a sliding of said 
layers along the rods, and if necessary, of the subsequent replacement of 
the rods by means of threads in a final lacing phase. 
The compression with sliding of the layers of thread along rods is 
accomplished preferably by the intermittent application of pressure on 
each new layer completed, the overall assembly of superimposed layers 
being held at its base by a supporting surface which moves away in a 
continuous motion from the thread-deposit area in order to make room for 
the new layers of thread to be deposited. 
It is desirable that the thread be deposited without tension in the network 
of rods, and to this purpose it is delivered by mechanical thrust, on 
demand, in a direction generally parallel to the direction of the rods. 
The thread can be deposited in windings oriented in the layers, 
superimposed alternately, first in one direction and then in another, 
crossing the first, for example, perpendicular to it (in this case, these 
two directions form a trirectangular trihedron with the direction of the 
rods). 
Thus, the process according to the invention makes it possible to perform 
the weaving in three dimensions of shaped pieces of complex design and any 
dimensions, by the deposit in the free spaces of the rods which define one 
direction of the piece to be produced, and with a thread following any 
direction at right angles to the preceding one, This thread comes from a 
single bobbin and it is reeled mechanically from above the rods (which are 
assumed to be arranged vertically), at the level of the top of the rods 
and parallel to their long direction. When a layer of thread is deposited, 
it is compressed at the same time that the component intended to hold the 
piece during the course of production is shifted in order to permit the 
deposit of the next layer. When the directions perpendicular to the rods 
have been materialized by the thread according to this method of thread 
deposition or weaving, these rods are removed in the course of a terminal 
operation called lacing, and they are replaced by a thread, preferably 
according to the process described in U.S. Pat. No. 4,393,669, to the 
present applicant. U.S. Pat. No. 4,393,669 is also incorporated here by 
reference. 
Likewise, rods formed from a material remaining in the piece can also be 
used, examples of these being pulp-extruded rods, and therefore, in this 
case, it is evident that the lacing operation is not applicable. In this 
case the rods remain as part of the thread package. 
By virtue of this process, it is possible to change at will, in each layer, 
the direction of the thread deposited at the top of the rods, in 
accordance with the stresses to which the woven piece or package is likely 
to be subjected. This is not the case in the known processes, in which, in 
general, the precise direction of the thread is dictated by the methods of 
operation of the process used. 
In addition, the process according to the invention, makes it possible to 
eliminate any system for stopping the threads introduced perpendicularly 
into the network of rods, and this leads, therefore, to the construction 
of a very simple machine. 
Finally, the arrangement provides for a single bobbin which facilitates 
monitoring of the reeling out of the thread. In the prior art, it is 
generally necessary to provide several bobbins in order to feed the 
needles which make it possible to introduce the threads into a given 
layer, these bobbins being equipped with devices for reeling the thread 
and for applying tension, and even for braking movement of the thread, in 
order to cause a given quantity of thread to arrive at each one of the 
bobbins for the creation of a layer, and without tension, so as not to 
deform the network of rigid pins or rods. The process according to the 
invention makes it possible to avoid these requirements. 
The invention also concerns a machine which makes it possible to use the 
previously-described process. This machine comprises, arranged on top of 
each other in a stationary housing, an assembly of three horizontal 
frames, which do not rotate but are independently movable vertically, 
among which, the intermediate frame has a set of horizontal plates 
provided with orderly perforations of regular design and intended to 
receive rigid rods of equal length which are thus held in a regular 
vertical network. The upper frame is equipped, by means of a displacement 
mechanism in accordance with two horizontal crossing directions, which are 
preferably perpendicular, with a shuttle which is thus movable in any 
direction on a horizontal plane, located slightly above the top of the 
network or rods, and capable of depositing on the top of same a thread 
which follows a winding path. The lower frame is equipped with a 
horizontal stopping plate, not perforated, subjacent to the network of 
rods. It is understood that the machine just described will meet the 
requirements if the rods are made from material remaining in the piece, 
such as paste-extruded materials, for example. In this case, the initial 
operation of weaving or thread deposition is the only operation necessary 
in order to obtain a three-dimensional weave. This same machine will 
likewise meet the requirements in cases in which--after the weaving has 
been performed on rods which are to be replaced by threads--it might be 
desired, for reasons of convenience of production, for example, to carry 
out the final operation of lacing at a different work station. But it 
might be useful for the same machine to perform the final phase of lacing, 
as well. In this case, it is advisable that the machine be equipped with a 
lacing device, in addition in order to make it possible to replace the 
rods with threads, after the initial thread deposition or weaving is 
completed. This lacing accessory consists, preferably, of an upper device 
to actuate a lacing needle, and a lower device for introduction of the 
lacing thread, these devices being installed in the respective mechanisms 
of displacement in two crossing horizontal directions, mounted, 
respectively, on the upper frame and on the intermediate frame. 
Advantageously, the machine's shuttle includes means for pulling and 
pushing the thread, capable of ensuring the delivery of the thread without 
tension, and consisting of two rollers between which the thread is held, 
and one of which is put into rotation by a motor. These rollers, push the 
thread, after it is deposited, into a vertical thread-guide. 
In addition, the machine is preferably equipped with a perforated 
horizontal plate, capable of descending over the network of rods, so that 
the rod ends then penetrate these perforations, thus compressing the 
layers of woven thread in said network. This perforated plate can be 
installed on the upper frame, above the shuttle, which is moved away from 
the rods from time to time in order to permit said perforated plate to 
descend onto the layers of deposited thread. 
Below the network of rods, the stopping plate can consist of a disk driven 
in rotation around its vertical axle, and comprising a vibrating bar which 
ensures, by sweeping under all the rods in turn, the longitudinal position 
of the rods at a constant average height, despite the frictional downward 
pull they are subjected to by the thread package in the course of 
production. 
It is desirable to combine with the machine according to the invention, a 
numerical control device to pilot and synchronize, according to a 
pre-established program, all of the operations of its movable parts, 
especially those of its shuttle, which define the configuration of the 
winding paths for deposit of the thread which form the successive layers 
of the package.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
In the drawings, no importance should be attributed to the fact that the 
number of rods of the network varies from one figure to the other. It is 
done this way for the simple reason of convenience of representation and 
understanding. In practice, the number and the arrangement of the rods are 
selected in accordance with the conformation and dimensions of each thread 
package to be produced. 
The machine represented in FIG. 1 comprises a housing 1, in which are 
installed, between its base 1a and its roof 1b, several stationary 
vertical threaded pins 2 (at least three), along which three horizontal 
frames, 3,4, and 5 can move. To this end, each one of these frames is 
provided with its own motor (not shown) in order to drive in rotation, by 
means of a chain 6, nuts engaged on the aforesaid threaded pins (only one 
of these nuts 6a of the single frame 4 has been shown, with the 
corresponding portion of chain 6). Each frame can thus be moved, at will, 
either upwardly or downwardly under the control of that motor. 
In other words, each frame 3, 4 and 5 has its own chain 6 which is movable 
by a motor. Each frame 3, 4 and 5 also has its own set of nuts 6a, each 
threaded onto one of the threaded rods 2, and each rotatable by movement 
of the chain 6. When the motor is driven to move the chain, each of the 
nuts 6a of the respective frame rotates to raise or lower that frame. 
Since the chain for each plate is rotatable independently of the chain for 
any other plate, the frames are movable independently of each other. 
The upper frame 3 is equipped with a perforated plate 7, and by means of a 
displacement mechanism 8 providing crossing movement, a shuttle 9 which 
performs the deposit of a thread 10 in a network 14 of rigid metal rods 
11, held vertically in a regular distribution by perforated plate 12 and 
13 (the number of plates 13 depends on the height of the piece to be 
produced), carried by intermediate frame 4. The perforations of plates 7, 
12 and 13 are arranged according to gridlines (straight, as shown in this 
illustration, or oblique), in such a way that rods 11 of network 14 which 
crosses them causes the appearance among them of channels which cross each 
other at a certain angle, in this case a right angle, into which the 
thread 10 is deposited by shuttle 9, according to alternating 
perpendicular changes of direction. The lower most perforated plate 13 is 
attached to lower frame 5 by means of clamps 51. 
Mechanism 8 which causes the displacements of shuttle 9 comprises a 
horizontal guide bar 15, along which the shuttle can move, actuated by a 
motor 16 through the medium of a transmission belt located inside the 
guide bar 15 (FIG. 2). The guide bar 15 is itself movable in a 
perpendicular horizontal direction, and its ends roll along guide rails 
17,18 attached to upper frame 3, under the action of transmission belts 
19,20 driven by a motor 21, likewise secured to frame 3. Shuttle 9 can 
thus move in two perpendicular horizontal directions 22 and 23, and 
therefore it can be moved successively to any point on the horizontal 
plane limited by rails 17,18. 
Shuttle 9 (FIG. 3) consists of a carriage 24, which slides along guide bar 
15 and is equipped with a small step motor 25 and two rollers 26 and 27 
between which the thread 10 is clamped. Roller 26 is driven in rotation by 
motor 25, while roller 27 is mounted for idle rotation. By command of 
motor 25, thread 10 is pushed more or less rapidly into vertical 
thread-guide tube 28, attached to plate 42 of carriage 24, and passing 
between the upper ends of rods 11 of the network 14, in order to deposit 
the thread on top of the network in accordance with the winding path 
selected. 
In order to make a thread package of specific shape on the machine 
described, rods 11 are first of all engaged through perforated plates 
12,13 in order to arrange them in a regular network 14 offering the shape 
desired (in this case, it is a cylindrical shape of circular or polygonal 
section). Since frame 3 is placed at such a height that the thread-guide 
tube 28 of shuttle 9 will penetrate into the upper part of network 14 
(FIG. 3), the shuttle is moved by its mechanism 8 along a winding course 
the turns of which are oriented in accordance with one of the directions 
of the orthogonal channels of network 14, parallel to the directions of 
displacement 22,23 of shuttle 9. At the same time, the shuttle's motor 25 
is put in operation, so that thread 10, coming out of bobbin 29, is 
deposited on the top of the network or rods in accordance with that 
winding path between the upper ends of the latter (FIG. 4). Deposit of the 
thread without tension is accomplished by means of a speed of output of 
the thread from the shuttle, synchronized with the speed of displacement 
of said shuttle. 
When a layer C of thread has been deposited, the next layer C is deposited 
in superimposition on top of it, in accordance with the other direction 22 
or 23. Upon the completion of each layer, shuttle 9 is caused to move to 
one side, and the downward displacement of frame 3 is ordered so as to 
cause the perforated plate 7 (FIG. 5) to come down onto network 14, for 
the purpose of compressing the mass 30 made up of all of the layers C 
produced. In order to ensure easy penetration of rods 11 into the 
perforations 31 of plate 7, the ends of the rods are ground to a point and 
the perforation openings are flared, as shown. In a parallel manner, frame 
4 is caused to descend from a distance approximately equal to the 
thickness of one layer, so that mass 30 will descend gradually, held by 
perforated plate 12 attached to frame 4 and compressed by perforated plate 
7, attached to frame 3. After each operation of compression, in which 
perforated plate 7 always descends to the same level, it is caused to rise 
again (by the upward movement of frame 3), up to a likewise fixed level, 
sufficient to make room for shuttle 9 between said perforated plate and 
the ends of rods 11, so it can return to that space in order to effect the 
deposit of a new layer of thread after having reabsorbed the space 
required by its movement to one side prior to the compression. 
It will be recalled that the frames 3 and 4 each have their own drive chain 
6 and threaded nuts 6a for effecting upward and downward movement of each 
frame. It should also be understood that the rods 11 can slide with 
respect to the perforated plates 12,13. This sliding, however, is impeded 
by the fact that the rods have thread 10 wrapped around them. Friction 
between the rods and the threads tend to make the rods move along with the 
woven mass 30. A relative movement between the rods and the woven mass 30 
is effected using a mechanism connected to the lower frame 5 as will be 
discussed below. It should also be remembered that the left hand side of 
FIG. 1 shows the mechanism during a weaving stage when the woven mass 30 
is being formed while the right half shows a lacing stage. 
The rods are linked by friction to the mass 30 as noted above, and they are 
therefore pulled downward at the time of the descent of frame 4. In order 
to compensate for this effect, under the network of rods there is provided 
and carried by frame 5 (of adjustable height), a disc 32, driven in 
rotation under the effect of a motor gear reducer 46, through the medium 
of a chain 48 and a toothed gear 50, equipped with a vibrating bar 33 
(FIG. 6), seated in the disc 32 by a pair of vertical-action vibrators 44 
(one shown) which are connected under disc 32. The rotation of the 
rotating assembly 32, 33 and 44, allows bar 33 to sweep under all the rods 
in the set of rods which it strikes successively and causes them to rise, 
thus cancelling the descent caused by the descent of frame 4. Therefore, 
rods 11 retain a constant overlap with respect to the last layer 
deposited, thus permitting the deposit of the next layer under the the 
same conditions as the preceding layer. At the end of the thread laying 
operation, frame 4 is located near frame 5, and perforated plates 13, 
suspended by chains 34 attached to frame 4, have consequently become 
juxtaposed. 
The mass 30 is then completed and can be transferred, as applicable, either 
to a binder impregnation station, or to another machine or work station in 
order to carry out the terminal phase of lacing (if used). But the machine 
covered by the invention can also carry out this terminal phase in order 
to produce the three-dimensional mass 30a. To this end, the machine is 
equipped with a lacing accessory 35 (already described in the applicant's 
U.S. Pat. No. 4,393,669 incorporated here by reference) consisting of an 
upper device 35a (FIGS. 2 and 3 of U.S. Pat. No. 4,393,669 and an upper 
device 35b (FIG. 7 of the same patent). These devices are shown together 
in the right-hand portion of FIG. 1 of the present application. The upper 
device 35a is installed on frame 3 through the medium of a displacement 
mechanism 36a providing for two orthogonal directions, similar to 
mechanism 8 of shuttle 9. The same is true for lower device 35b, the 
displacement mechanism 36b of which is mounted on frame 4. These lacing 
assemblies are removable. 
In the lacing phase, frame 4 which carries the woven piece by means of its 
perforated plate 12 (the lift called for in the weaving phase having been 
eliminated) is raised to a height to allow a sufficient space below for 
the descent of rods 11a, displaced by woven mass 30. The frame is lifted 
correspondingly to a position in which its perforated plate 7 rests on the 
top of woven mass 30. According to the assertions of the already cited 
U.S. Pat. No. 4,393,669, the upper device 35a causes a long needle 41 to 
descend successively plumb with each rod 11, so as to remove it and cause 
it to fall to 11a under frame 4, onto disc 32 (while it remains held by 
perforated plates 13, now reassembled and held at the top of columns 38). 
At each descent, the aforesaid needle threads lower into device 35b a 
thread 39 coming from a bobbin 40 and pulls it in a loop through woven 
mass 30 in replacement of the rod it has just forced out, thus 
transforming mass 30 into a three-dimensional mass 30a. Naturally, the 
displacement mechanisms 36a and 36b are controlled correspondingly in the 
same way so that the lacing devices 35a and 35b will constantly be 
opposite each other and will successively be plumb with each rod of 
network 14. 
Control of the various movable components of the machine, especially 
displacement mechanisms 8, 36a and 36b (equipped with step motors), is 
effected in synchronization, in each phase of operation, by means of a 
numerical control device of a classic programmable type well known to 
technicians and not forming a part of the present invention, into which 
there is introduced a program corresponding to the characteristics of 
structure, shape and dimensions of the thread package or woven piece to be 
produced. 
It is understood that, through the choice of this program, it is possible 
to obtain the deposit of the thread by shuttle 9 in each layer, in 
accordance with any desired winding path among rods 11 of the network. 
Moreover, these rods can be arranged in a transverse section of any shape 
and geometric disposition. It is also possible to obtain pieces of any 
shape, solid or hollow, or even deformable if the path for deposit of the 
thread is selected to that end in each transverse layer. 
This numerical control is a standard numerical control designed to control 
milling machines and capable of operating three shafts simultaneously, and 
of controlling the output (all or nothing) which might be required in the 
program for production of the package. Such a control is commercially 
available for milling machines and can be used for the present invention. 
The lower frame is movable only by manual control of the operator 
accomplished by pressing a respective button (not shown) on the numerical 
control unit. 
All of the functions involved in the deposit of the thread, i.e.,: 
rotation of the plate 32 which supports the vibrating bar 33, and start-up 
of the vibrator; 
descent of the intermediate frame 4 by the thickness of one layer; 
descent of the upper frame 3 in order to compress the layers of thread 
deposited; 
lifting up of the upper frame 3; and 
simultaneous rotation of the three step motors, i.e., the two shuttle 
displacement motors and the motor which thrusts the thread; 
are the result of instructions from the program which defines a thread 
package and the re-entry into numerical control. 
While a specific embodiment of the invention has been shown and described 
in detail to illustrate the application of the principles of the 
invention, it will be understood that the invention may be embodied 
otherwise without departing from such principles.