Process for the mounting of a group of component parts on a support element, in particular parts of a timing gear of a heat engine, and a packing print for carrying out this process

The packing print for receiving in particular component parts (2-7) of a timing gear of a heat engine provided with a camshaft and a crankshaft, comprises cavities (2a, 3a, 4a, 5a) adapted to receive the component parts (2-7), in particular a camshaft wheel (2), a crankshaft pinion (3), a tension-producing device (5) and a guiding device (7) for a transmission chain (4) or belt associated with the pinion (3) and the wheel (2), these cavities being so arranged that the component parts (2-7) received therein are pre-positioned and pre-oriented with respect to one another in the exact positions they must occupy on the engine so as to permit the mounting of the component parts simultaneously on the engine. This print permits carrying out the mounting very rapidly with no risk of error in the positioning of the component parts.

The present invention relates to a process for mounting a group of 
component parts on a support element in given relative positions and 
orientations, and in particular parts of a timing gear of a heat engine, 
and to a packing print for carrying out this process. 
It is known that on present assembly lines of engine producing units, the 
various parts required for the driving of the camshaft, and possibly other 
accessories such as an injection pump, are mounted in succession at one or 
more work stations. For example, there are mounted in succession the 
crankshaft toothed pinion, then the element or elements for putting under 
tension and guiding, then the shaft toothed wheel, and lastly the 
transmission element constituted by a chain or a belt. 
In the course of these mounting operations, the specifications of the 
relative setting between the various elements, in particular the setting 
between the crankshaft, the camshaft and possibly the injection pump, must 
be scrupulously conformed to. It is found at the present time that the 
mounting of the parts of a timing gear of a heat engine thus involves: 
the procurement, the handling, the storing and the managing of a large 
number of parts, 
a great number of mounting operations requiring considerable time, numerous 
persons and a large amount of space, 
multiple operations which are difficult to render automatic, 
a care and attention in these mounting operations which, while requiring a 
large amount of time, necessitate checkings for detecting possible error 
in the assembly which might result in the destruction of the engine when 
it is operated for the first time. 
An object of the invention is therefore to avoid these requirements and 
inconveniences by providing a process for mounting component parts on the 
support, and a print or packing for carrying out this process which 
substantially improves the productivity and the reliability of the 
mounting of the various parts of the assembly. 
The invention provides a mounting process comprising disposing the parts in 
a print where they are pre-positioned, pre-oriented and maintained in 
positions corresponding to those that they must occupy on their support 
element, then presenting this print, with the parts placed therein, in 
front of the support element in accordance with the suitable orientation, 
fixing said parts to the support element without extracting them from the 
print and, after the fixing of the parts, removing the print. 
This process, which is applicable to each case where a g r o u p of parts 
must be assembled on a support element in well-defined positions and 
orientations, has many possible applications in the mechanical industry, 
and in particular in the automobile industry, but also in other various 
industrial fields such as electric, electronic and and building 
engineering, etc.. 
In the case where the process according to the invention is applied to the 
mounting on a heat engine comprising a camshaft and a crankshaft of parts 
of a timing gear of this engine, the process comprises packing the parts 
of the timing gear in a print in which are formed receiving impressions 
for the various parts dimensioned and arranged in such manner as to g r i 
p said parts so as to retain them in the case of an over-turning of the 
print and to assure the positions and the orientations of the parts of the 
timing gear according to the exact positions and orientations they must 
occupy on the engine, then presenting this print with the parts in front 
of the engine, fixing the parts to the latter while they are still in the 
print, owing to the provision of openings in the print which permit 
passing the means for fixing the parts and then removing the print. 
Another object of the invention is to provide a print for carrying out this 
process and the assembly constituted by the print provided with the 
component parts. 
The invention provides a packing print for an assembly of component parts 
on a support element adapted to carry out the aforementioned process and 
comprising cavities adapted to receive various component parts and for 
pre-positioning and pre-orienting the parts with respect to one another in 
the exact positions that they must occupy on the support element, said 
cavities being so dimensioned as to grip the component parts so as to 
retain them during the handling of the print before mounting the parts on 
the support element, openings being provided in the print to permit the 
passage, from the rear of the print, of elements for fixing the parts on 
the support element while the component parts are still in the print. 
According to an embodiment of the print more particularly adapted to 
receive component parts of a timing gear of a heat engine, the print 
comprises cavities adapted to receive the component parts of the timing 
gear, in particular a camshaft toothed wheel, a crankshaft toothed pinion, 
elements for putting under tension and guiding a transmission chain or 
belt associated with the pinion and with the wheel, and said cavities are 
so arranged that the component parts received therein are pre-positioned 
and pre-oriented with respect to one another in accordance with the exact 
positions that they must occupy on the engine, so as to permit the 
mounting of the component parts simultaneously on the latter. 
As the print is made for example from a plastics material in the form of a 
block of rigid foam or a thermoformed sheet, the cavities are so 
dimensioned that their walls g r i p the corresponding component parts and 
openings for the passage of elements for fixing the component parts are 
provided in the print, in particular for screws for fixing the camshaft 
toothed wheel, the crankshaft toothed pinion, a tensioning device and a 
guide for the transmission element and, possibly for other accessories 
such as a toothed wheel for an injection pump. 
Thus, as the component parts of the timing gear are previously pre-mounted 
and pre-positioned with respect to one another, in the positions that they 
must occupy when mounted on the engine, it is sufficient to present in a 
single unit the print provided with the component parts in front of the 
end of the engine and then carry out the fixing operations without 
previously extracting the component parts from the print; these operations 
may if desired be advantageously rendered automatic and effected 
simultaneously.

FIGS. 1 to 5 show a print or packing 1 made from a suitable rigid foam of 
plastics material such as polyethylene foam and adapted to receive the 
component parts of a timing gear of a heat engine M (FIG. 5) provided with 
a camshaft 22 and a crankshaft 23. 
The print or impression 1 comprises cavities adapted to receive the 
component parts of this timing gear, namely, in the presently-described 
example: a cavity 2a in which may be placed a camshaft wheel 2, a cavity 
3a receiving a crankshaft toothed pinion 3, a cavity 5a which opens onto 
the cavities 2a, 3a and receives an element for transmitting motion 
between the pinion 3 of the crankshaft 23 and the wheel 2 of the camshaft 
22, constituted in the presently described example by a chain 4 engaged on 
the wheel 2 and the pinion 3, this chain 4 extending consequently also in 
the cavities 2a and 3a. The cavity 5a also receives a strip 6 which is 
part of the tensioning device 5 and which is applied against the slack 
side of the chain 4. 
The taut side of the chain 4 extends in a cavity 4a which is extended 
laterally and in its upper part by another cavity 7a which receives a 
guide 7 having an L-section shape of which one branch extends in the 
cavity 4a and carries a bearing member 7b in contact with the taut side of 
the chain 4. 
The print 1 is provided with a first opening or clearance 8 providing 
access to a screw 10 fixing the wheel 2 to the camshaft 22 (shown in 
dot-dash lines in FIG. 2), a second opening 9 opening onto the cavity 3a 
and permitting access to a screw 11 for fixing the pinion 3 to the 
crankshaft 23 (shown in dot-dash lines in FIG. 2). Two other openings 14a, 
14b open onto the cavity 5a and allow access to two screws 15 fixing the 
tensioning device 5 to the engine M, two openings 16 are provided under 
the guide 7 and permit access to two screws 18 for fixing this guide 7 to 
the engine, and an opening or clearance 17 communicates with the cavity 5a 
in the vicinity of the pinion 3 and permits access to a screw 19 for the 
pivotal mounting of the strip 6 on a spacer member 20. 
The openings 8, 9, 14a, 14b, 16, 17 formed passages in the print 1 and 
therefore permit access through the rear of the latter to the respective 
screws 10, 11, 15, 18 and 19. 
A fool-proof device, constituted in the presently described example by a 
boss 12 of the print 1, enters an aperture 13 of the wheel 2 so as to 
guarantee its orientation relative to the pinion 3 without ambiguity. 
The end of the engine M is provided with screwthreaded holes 15a, 18a and 
19a adapted to receive the screws 15, 18 and 19 respectively (FIG. 5). 
All the cavities 2a, 3a, 4a, 5a . . . mentioned above are so dimensioned 
that the corresponding component parts 2, 3, 4, . . . can be received 
therein only by exerting a slight force so that the walls of these 
cavities grip these parts and hold them in position irrespective of the 
orientation of the print 1 provided with the component parts of this 
timing gear during its handling before mounting on the engine M. In 
particular, this gripping prevents the parts from falling away from the 
print when the latter is completely turned over. 
The mounting process according to the invention carried out with the print 
1 just described is as follows. 
With all the component parts described above pre-positioned and 
pre-oriented suitably in their cavities in the exact respective positions 
they must occupy on the end of the engine M, the print 1 is presented with 
the component parts in a vertical position in front of the engine M (FIG. 
5), the wheel 2 and the pinion 3 are respectively engaged on the camshaft 
22 and the crankshaft 23 and fixed in position by means of the screws 10, 
11. The tension producing element 5 and guiding element 7 are then screwed 
in position by screwing the corresponding screws 15, 18 and 19 in their 
holes 15a, 18a, 19a. By way of a modification, the print 1 may be 
presented advantageously by means of a robot 25 and all the screwing 
operations may be advantageously carried out simultaneously and 
automatically by a screwing device 24 (FIG. 5). 
Finally, the print 1 is removed or torn away since the mounting is now 
finished. 
The invention affords important advantages to manufacturers of engines: 
the procurement of supplies, the handling, the storing and the management 
of a single unit ie. the print provided with its component parts; 
all of the component parts of the timing gear are mounted simultaneously at 
a single work station so that there is a saving in time, personnel and 
space which is considerable; 
the mounting operation may be rendered automatic by means of a robot such 
as 25 and a screwing device such as 24, all the screwing operations being 
then simultaneous; 
the use of the print or packing 1 renders any mounting or assembly error 
impossible, the specifications of relative setting between the various 
component parts being assured by the arrangement of the cavities receiving 
these parts. 
The second embodiment of the print according to the invention, illustrated 
in FIGS. 6 to 9, differs from the first embodiment in that the print lA is 
here constituted by a thermoformed sheet. In the latter, the cavities 2a, 
3a, . . . of the various component parts are identical to those of the 
print 1. On the other hand, the openings or clearances 8A, 9A, 14A, 16A, 
17A corresponding to the openings 8, 9, 14, . . . of the first embodiment, 
are here constituted by simple apertures in the sheet 1A, with respect to 
which the screws 10, 11, 18, . . . project. The boss 12 of the print 1 is 
replaced in this second embodiment by a hollow boss 12A for centering the 
wheel 2. 
It must be understood that the scope of the invention is not intended to be 
limited to the embodiments described hereinbefore since many 
constructional variations may be envisaged, in particular due to the fact 
that various other accessories (not shown), such as an injection pump 
wheel, may be provided in cavities provided for this purpose in the print. 
As already mentioned, the invention is applicable to fields other than the 
automobile industry.