System for coupling two bodies, for example a carriage and a machining station

This invention relates to a system for coupling two bodies able to move relatively with respect to each other by a given incertainty of amplitude, essentially characterized in that it comprises, on a first body, a projecting part having an end section of determined value and members for controlling the displacement of said projecting part with respect to said first body, and, on the second body, a cavity having an inlet opening whose section has dimensions larger than those of the end of the projecting part, the valve of the difference between these two sections being at least equal to that of the given incertainty, and members for exerting at least one couple of reaction forces between said projecting part and the inner wall of said cavity. The invention is more particularly applicable to the systems for coupling carriages and work stations in so-called flexible workshops.

The present invention relates to systems for coupling two bodies such as, 
for example, a carriage and a machining station such as those found in 
places of the "flexible workshop" type. 
In order to increase profitability in modern machining techniques, 
so-called "flexible" workshops have been created which schematically 
comprise an assembly of machining stations distributed in predetermined 
manner according to the functions which are to be performed, and at least 
one carriage which may move in an independent manner, guided by different 
means, for example optical, magnetic, electrical, etc. . . . , in order to 
be coupled with the machining stations to furnish them with products or 
tools necessary for their respective functions. For such a carriage to be 
able to serve a work station optimally, the coupling system according to 
the prior art require that it be perfectly positioned with respect to this 
work station. The design of the means for guiding the carriages is 
therefore very complex and they are of very high cost. Moreover, these 
complex guiding means are subject to relatively frequent breakdowns, which 
contributes to increasing the overall cost of the flexible workshop even 
further. 
It is an object of the present invention to produce a system for coupling 
two bodies, such as a carriage and a machining station in a workshop of 
the flexible type, which makes it possible to connect one of the bodies to 
the other even if the two bodies are not perfectly positioned with respect 
to each other, which is simple to produce, easy to use and highly 
reliable, whilst contributing to reducing the cost of the flexible 
workshop that it equips. 
More precisely, the present invention relates to a system for coupling two 
bodies able to move relatively with respect to each other by a given 
uncertainty of amplitude, characterized in that it comprises, on the one 
hand, on a first body, a projecting part having an end section of 
determined value and means for controlling the displacement of said 
projecting part with respect to said first body, and, on the other hand, 
on a second body, a cavity having an inlet opening whose section has 
dimensions larger than those of said end of the projecting part, the value 
of the difference between the dimensions of these two sections being at 
least equal to that of the given uncertainty, and means for exerting at 
least one couple of reaction forces between said projecting part and the 
inner wall of said cavity.

Referring now to the drawings, FIG. 1 shows, by way of example of 
application of the coupling system, a flexible workshop 1 comprising, for 
example, three work stations 2, 3, 4 such as for example machine tools for 
machining mechanical workpieces such as drilling machines, autolathes, 
lathes, etc. . . . 
These stations respectively comprise an entrance platform 5, 6, 7 via which 
they may be automatically supplied with workpieces to be treated. In 
modern workshops, these work stations are supplied by carriages on which 
the workpieces to be treated are placed. In the example illustrated, only 
one carriage 8 has been shown. This carriage is automatically guided by 
means of different sensors, for example of optical, magnetic, mechanical 
etc. . . . type and programmed to follow a certain path 9. As mentioned 
hereinabove, with the coupling systems according to the prior art, it is 
necessary that this programmation allow the carriage to move very 
precisely with respect to the work station. On the other hand, with the 
coupling system as illustrated in FIGS. 2 to 6, it is possible to use a 
carriage guiding device which is much less elaborate. 
These Figures illustrate a system for coupling any two bodies 11, 12 which 
may in fact be the carriage and a work station according to FIG. 1 and may 
move relatively to each other with a given uncertainty of amplitude. 
The first body 11 comprises a projecting part 13 advantageously of oblong 
shape, such as for example a rod 14 whose end 15 has a section the shape 
of which decreases progressively, giving it a substantially conical shape. 
With this projecting part are associated means 16 for controlling its 
displacement with respect to the first body 11. 
The second body 12 comprises a cavity 17 having an entrance opening 18 
whose section has a dimension larger than at least that of the end 15 of 
the projecting part 13, the value of the difference between these two 
sections being at least equal to that of the uncertainty of the amplitude 
of the relative movements of the two bodies 11 and 12 mentioned 
hereinabove, when they must be coupled to each other. In an advantageous 
embodiment, the smallest inner section over the whole length of the cavity 
17 is greater than the largest section over the whole length of the 
projecting part 13, the value of the difference between these two sections 
likewise being at least equal to that of the given incertainty defined 
hereinabove. In this way, the projecting part 13 may penetrate into cavity 
17 over a relatively large distance, ensuring a reliable and efficient 
coupling. 
The system further comprises means 19 for exerting at least one couple of 
reaction forces between the projecting part 13 and the inner wall 20 of 
the cavity 17. These means may be constituted by jacks 60, for example of 
the conventional type with rod and cylinder and controlled electrically or 
hydraulically, the cylinders 61 being fixed to the projecting part 13, 
preferably embedded in its mass, with the result that only the rods 62 can 
emerge laterally from this projecting part. The jacks 60 are located in 
that portion of the projecting part adapted to penetrate in the cavity 17 
and the outer ends of the rods are advantageously provided with pads 63 
whose shape allows them to retract in the lateral wall of the projecting 
part 13, when the rods of the jacks are retracted, in order not to hinder 
the movement of translation of this projecting part which will be 
mentioned hereinafter, and in order better to fit the shape of the inner 
wall 20 of the cavity 17. In an advantageous embodiment, the device may 
comprise three jacks whose rods will be oriented in order to move in 
directions at one hundred and twenty degrees with respect to one another, 
as shown in FIG. 2. 
The cavity 17 is advantageously made in a head 21 mounted on the second 
body 12 so that it has at least one degree of freedom of displacement. In 
the embodiment illustrated, the head 21 is mounted mobile about two axes 
of rotation 22, 23. It is thus connected to a rotating shaft 24 which 
allows it to pivot with respect to a frame 25 itself mounted to pivot 
about axis 23 on the second body 12, these two axes forming therebetween 
an angle different from a plane angle, and advantageously a right angle, 
in order to be able to orient the axis 26 of the extrance of the cavity in 
a solid cone having a vertex angle value as a function of the given 
incertainty mentioned hereinabove. 
As mentioned hereinabove, the axis 26 of the entrance of the cavity may be 
oriented to accept a solid cone. The same applies to the axis of the 
projecting part 13, by means 16. These means comprise, in a possible 
embodiment, a base 30 mounted to pivot about an axis 31 on a plate 32 
mounted on the first body 11, itself pivoting about another axis 33, for 
example and advantageously perpendicular to axis 31. 
The coupling system also comprises means 34 for mounting the projecting 
part 13 in translation with respect to the base 30. An embodiment of these 
means is illustrated in FIG. 2. They are constituted by a slide 36 mounted 
on guiding slideways 37, for example rectilinear, located in a housing 38 
made in the base 30, the projecting part being mounted fast with the slide 
36. Displacement in translation of the slide with respect to the base is 
obtained, for example, by a drive by any means of which the reciprocating 
movement is obtained by a motor (not shown in order to simplify the 
drawing) or by an equivalent means such as a jack. 
For correct and repetitive functioning of the coupling system described 
hereinabove, the latter further comprises means 40 for returning the 
projecting part 13 and base 30 into an original position relative to first 
body 11, as well as means for returning the cavity 17 and head 21 into an 
original position relative to the second body 12 (see, e.g., the relative 
movement of first body 11/base 30 and second body 12/head 21 in FIGS. 
4-6), these positions in fact advantageously being mean positions in the 
possible volume of displacement as defined hereinbefore of the two bodies 
11 and 12 with respect to each other. These means may thus cooperate 
between, for example, the head 21 and the frame 25, between frame 25 and 
the second body 12, to return the cavity 17 to an original position, and 
also between the base 30 and the plate 32, between the plate 32 and the 
first body 11, in order automatically to return the projecting part 13 to 
an original position. 
FIG. 3 shows a possible embodiment for such means 40. In that case they 
comprise a catch 41 connected tp a first, 42, of the elements mentioned 
hereinabove (e.g., frame 25 or plate 32) and means 43 for exerting on this 
catch 41 two elastic forces of opposite directions, these means being able 
to be constituted by two springs 44, 45 for traction or thrust, one of 
their ends 46, 47 being respectively connected by pusher elements 48, 49, 
to the catch 41, their other two ends 50, 51 being respectively connected 
to the other second element 52 with respect to which the first element 42 
must be repositioned (e.g., second body 12 or first body 11 respectively). 
In this way, when an effort is exerted on one of the two elements 42 or 52, 
teh catch transmits it via one of the pusher elements 48, 49 to one of the 
two springs 44, 45 which is compressed and which thus increases its 
reaction force in order to attempt to compensate that of the effort, 
whilst the other spring exerts no action. When the effort on the element 
is cancelled, the spring no longer being subjected to a counter-force, it 
slackens and attempts to return the pusher element to its stop position 
against an inner stop 54, 55. As the end of the pusher elements acts on 
the catch 41, the latter is returned to its predetermined original 
position, as well as the element 42 with which it is associated which may 
then participate in a new coupling. Since the means 40 for returning the 
constituent parts of the invention to a starting position (e.g. frame 
25/second body 12 and plate 30/first body 11) shown in FIG. 3 utilizes 
pusher elements 48 and 49 which are only capable of linear movement, this 
particular means 40 would only be useful in applications wherein the 
relative movement (e.g., between the frame 25/second body 12 and plate 
30/first body 11) would be significantly less than 360.degree.. If a 
greater scope of movement were desired, different means 40 for returning 
the constituent parts of the invention to a starting position relative to 
each other would be employed. 
The system described hereinabove operates as follows, this description 
being explained more particularly with regard to FIGS. 4 to 6. It is 
firstly specified that the first body 11, for example a carriage, may come 
into position, with a certain uncertainty in its placing, opposite the 
second body 12, for example a work station, this uncertainty being 
defined, for example, by the value of the maximum distance that may 
separate two points belonging respectively to the two bodies 11, 12, 
without the relative position of these two points being known with 
precision. 
FIG. 4 shows the two bodies 11, 12 approximately opposite each other, 
positioned, however, so that the projecting part 13 is contained in the 
projection of the entrance section 18 of the cavity 17. This condition is 
ia consequence of the respective values of the sections defined 
hereinabove. It is specified that the two elements, in the present case 
the projecting part 13 and the cavity 17, are disposed in their originial 
position with respect to their repsective bodies, thanks to the means 40 
for returning into original position, described hereinabove. 
When the two bodies are in the position as shown in FIG. 4, the projecting 
part 13 is controlled in translation on slideways 37 so that the conical 
end 15 penetrates into cavity 17, this being possible since the section of 
this end is smaller than that of the entrance 18 of the cavity 17. When 
this projecting part has penetrated into the cavity, its end abuts against 
the inner wall 20 of the cavity and the reaction force between these two 
elements obliges the two elements to be oriented with respect to each 
other, all the better as they have structures as described with reference 
to FIG. 2, knowing that this reaction occurs in opposition to that given 
by the means 40 for returning to an original position. 
Furthermore, it is also possible that this projecting part penetrates 
directly into the cavity without coming into contact with its inner wall 
20, as more precisely illustrated in FIG. 5. In one or the other case, 
when the projecting part has sufficiently entered the cavity, the jacks 19 
are extended so that their heads are applied against the inner wall 20 of 
the cavity. By the simple effect of the couple of opposite forces, on the 
one hand the axes of the projecting part and of the cavity are perfectly 
aligned and, on the other hand, the two elements are connected (FIG. 6). 
Since the head 21 and the base 30 are in alignment, the workpieces to be 
treated which are on the first body 11 may automatically pass onto the 
head 21 of the second body 12, providing for the example of use given 
hereinbefore. To that end, the base 30 and the head 21 may comprise drive 
chains 39 and 59 respectively, which may be coupled to supporting tables 
on which the workpieces to be treated or the machined pieces may be 
disposed. 
When such an operation is finished, the jacks 19 are retracted, the 
projecting part is returned into the housing 38 and the different elements 
are returned into the parts original position thanks to the means 40 for 
returning into original position. The two elements 13 and 21 are then 
ready to start such a coupling operation again, for the same two bodies or 
for another carriage with the same work station, or for the same carriage 
with another station, knowing that coupling means all identical to that 
described hereinabove may equip all the bodies of the same workshop. 
Such a coupling device does not present any major difficulty in use and it 
makes it possible to compensate the uncertainties of positioning the two 
bodies. Carriages provided with low-performance driving means may 
therefore be used, thus contributing to reducing the cost of the 
installation of a flexible workshop still further.