Method for producing a continuous band of rubberized fabric having transversal reinforcing metal elements

A method is disclosed for accurately and readily forming a continuous band of rubberized fabric having transversal reinforcing metal elements by butt-splicing wherein a first and second piece of rubberized fabric having transversal reinforcing metal elements are positioned such that the initial end of the second piece is a predetermined distance from the terminal end of the first piece on a common plane with the reinforcing metal cords running parallel to the ends of the pieces, butt-splicing the pieces, without overlapping, by mutually approaching the pieces, obtaining a uniform accumulation of the rubber of the rubberized fabric about the reinforcing cords as well as a local thickening of the latter at a zone symmetrically situated with respect to the contact surface of the ends and whose width is proportional to the pre-established distance wherein the pieces are bound by the operating parts of the splicing apparatus, releasing the pieces from the operating parts of the splicing apparatus and winding up the continuous band on a collecting drum. An apparatus for producing the continuous band is also disclosed where the operating parts have a base element and a movable ledger capable of locking the pieces of rubberized fabric on a common plane by a series of fingers.

It must be taken into account that, for the sake of convenience and 
simplicity of language, in the present description reference is made to a 
first and to a second piece, even if actually the so-called first piece is 
already generally constituted by a continuous band of rubberized fabric, 
formed by an indefinite number of previously butt-spliced pieces. 
The second piece is indicated in the present description with the reference 
numeral 2, although it takes three successive different positions on the 
apparatus during the working phase wherein it lies on the feeding roller 
plane, under the translating element and on the splicing apparatus. 
From FIGS. 1 and 2 it can be seen that the apparatus substantially 
comprises: a roller plane 1 for supplying the so-called piece 2 of 
rubberized fabric; a translating element 3 which picks up the piece 2 and 
locates it as explained herebelow; a splicing device 4 to butt-splice the 
initial end E of the so-called second piece 2 with the terminal end U of 
the so-called first piece 5; and a drum 6 for collecting the continuous 
band of rubberized fabric formed after the splicing of said pieces. 
The apparatus comprises moreover: a vertical plate 8 whose portion can be 
adjusted by means of a handwheel 9 in order that its surface directed 
towards the roller plane 1 and parallel to the lateral edges L of the 
first piece 5 be strictly aligned with one of them; and a motor 10 for 
winding up the band on the collecting drum 6. 
As shown in FIG. 2, the roller plane 1 is situated perpendicularly to the 
direction of motion of the translating element 3 (which moves in the 
directions of arrows F and F') (FIG. 1) and to the axis of the splicing 
device 4; this means that the roller plane is parallel to the direction of 
the reinforcing metal cords C of pieces 2 and 5, which are arranged 
"transversally", namely perpendicularly to the winding direction of the 
band of rubberized fabric on the collecting drum 6. 
The translating element 3 (FIGS. 1, 2, 6) comprises a metal plate 11 which 
is suspended, by means of a support 12 and of a hydraulic piston 13 having 
a vertical axis, to a vertical carriage 14 provided with wheels 15 which 
can slide on the wings of a beam 16 in the form of overturned T; the later 
is fixed to the roller plane 1 by means of a vertical stanchion 17 and to 
the splicing device 4 by means of a frame 18. 
The beam 16 carries, rigidly fixed to it, the body of a double-acting 
cylinder 19 whose stem 20 is instead fast with the carriage 14; therefore, 
permitting introduction of compressed fluid in the cylinder 19, in the two 
possible ways; it is possible to obtain the already mentioned senses of 
motion of the translating element 3, indicated by arrows F and F'. 
The plate 11 of the translating element 3 is provided with a series of 
electromagnets 21 which serve to keep the piece 2 hooked during its 
positioning on the splicing device. 
To this purpose, the plate 11 can moreover be raised and lowered by means 
of the vertical piston 13. 
The other highly relevant part of the present apparatus is constituted by 
the splicing device 4, illustrated particularly in FIGS. 2, 3, 4 and 5. 
Splicing device 4 comprises a rectangular support 22 provided at its 
corners with four vertical columns 23; said columns are connected together 
two by two, in a direction parallel to the direction of movement of the 
translating element 3, by means of two shafts 24, parallel to each other, 
on which are keyed two pistons 25 of as many double-acting cylinders 26. 
The central part of each shaft 24 is threaded and onto it is screwed a ring 
nut 27 for adjusting the stroke of the corresponding cylinder 26. 
As can be seen in FIG. 4, the body of each cylinder 26 is fast with a first 
hollow shaft 28 arranged with a certain diametrical clearance on the 
corresponding shaft 24 and, more exactly on the part of the latter which 
is here conventionally defined as "upstream" the ring nut 27. 
Around the part of each shaft 24 which is here conventionally defined as 
"downstream" the ring nut 27 is keyed a second hollow shaft 29, equal to 
the first hollow shaft 28 but made integral with the shaft 24. By 
adjusting the fluid under pressure in the two possible ways inside the 
double-acting cylinders 26, it is then possible to obtain horizontal 
movements of the hollow shaft 28 with respect to the hollow shaft 29, 
which remains stationary. 
Each pair of hollow shafts 28 and 29, respectively, is connected with one 
of the operating parts of the splicing device, respectively 30, 31, said 
parts being symmetrical to each other with respect to the vertical plane 
defined by the ring nut 27. 
Each of said operating parts 30 and 31 comprises a base element 32 and 33 
and a movable upper ledger 34 and 35 (FIG. 3). Each of the base elements 
32 and 33 is fast, respectively, with the hollow shafts 28 and 29 (FIG. 5) 
by a pair of vertical hollow shafts 36 and 37; therefore the base elements 
32 and 33 are stationary in the vertical sense. On its turn, each of the 
movable ledgers 34 and 35 is joined to a pair of vertical shafts 38 and 
39, mounted with a certain diametrical clearance in the vertical hollow 
shafts 36 and 37. 
The vertical shafts 38 and 39 can slide vertically inside the hollow shafts 
36 and 37; in fact they are inferiorly fast to the big ends of the 
connecting rods, 40 and 41 respectively; the small ends of the connecting 
rods are actuated by knurled stems 42, 43 of the double-acting cylinders 
44 and 45, which the interposition of a gear 46 and 47. 
Consequently, the admission of the fluid under pressure inside cylinder 44 
and 45 in either of the two possible ways determines the displacement of 
said knurled stems and therefore the lifting and lowering of the movable 
upper ledgers 34 and 35 (see FIG. 5). 
The base elements 32 and 33 comprise a first series of coplanar fingers 48 
and 49, intercalated with one another, which are situated at the ends to 
be spliced of pieces 2 and 5, and a second series of fingers 50 and 51, 
coplanar and integral with those of the first series, and lying at the 
side opposite to them with respect to the vertical plane passing through 
the axes of shafts 38 and 39 (see FIGS. 2 and 3). On their turn, the 
movable ledgers 34 and 35 comprise a first and second series of coplanar 
fingers, respectively 52 and 53, 54 and 55. The fingers belonging to the 
movable ledgers are superimposed to the fingers belonging to the base 
elements. As opposed to the fingers forming part of the base elements, the 
fingers forming part of the movable ledgers are not directly integral with 
the latter, but are fast to it through special inflatable chambers, 56 and 
57 respectively, enclosed respectively in the ledgers 34 and 35. 
By inflating said chambers 56 and 57, the fingers 52 and 53 are further 
lowered with respect to the respective movable ledgers after which the 
latter will have reached their low position, determined by cylinders 44 
and 45. 
The main features of the splicing device resides in the fact that the 
fingers 48, 49, 52, 53 have a "composite" surface (FIG. 7), in the sense 
that they present a first smooth surface, 48', 49', 52' and 53' 
respectively, in correspondence of two bands situated symmetrically at the 
two sides of the ends to be spliced of pieces 2 and 5, and a knurled part 
48", 49", 52" and 53", respectively. 
The distance, measured vertically, between the fingers belonging to each 
operating part is so chosen that it is always greater at the smooth 
surface of the fingers than at their knurled surface. This circumstance is 
noticeable in any moment of the operation of the present apparatus; 
therefore, when the splicing of the ends 2 and 5 is carried out in the way 
which will now be further illustrated, the distance between the fingers of 
each of the symmetrical operating parts 30 and 31 has a value A, at the 
smooth surfaces, which is greater than value B at the knurled surfaces 
(see FIGS. 7 and 8). 
Practically, the distance B is so pre-established that the pieces 2 and 5 
are blocked between the knurled surfaces 48" and 52", 49" and 53", while 
the distance A is such as to leave a vertical clearance between the 
surfaces of the pieces 2 and 5 and the smooth surfaces 48' and 52', 49' 
and 53' of the fingers. 
At last, it is to be noted that the fingers belonging to each of the 
symmetrical operating parts 30 and 31 engage with one another, when the 
movable ledgers, after having been lowered, are mutually approached during 
the splicing of the pieces 2 and 5; this means that there is always a 
certain interference between said fingers, on the planes containing them, 
namely that they are mutually intercalated. 
Coming now to the operation of the present apparatus, it begins when the 
so-called first rectangular piece of rubberized fabric 5 is situated with 
its terminal end U at the operating part 31, downstream the splicing 
device 4. More exactly, the terminal end U is situated in the position 
shown in FIG. 7, exception made for the circumstance that the movable 
ledgers 34 and 35 of the splicing device are lifted with respect to their 
respective base elements 32 and 33. Meanwhile, the so-called second piece 
2 (which has been previously cut to the desired size by means of two cuts 
perpendicular to the direction of its reinforcing metal cords with a 
cutter, not illustrated), travels on the roller plane 1 in the sense 
indicated by the arrow F* (FIG. 2). 
This movement of the second piece 2 terminates when its fore end S touches 
the vertical plate 8. 
As the position of the latter has been previously adjusted by means of the 
handwheel 9, so that its surface directed towards the side plane 1 is 
perfectly aligned with the lateral edges L of the first piece 5, the 
second piece is automatically oriented in such a way that its cords C are 
exactly parallel to the cords C of the first piece 5. 
In this position (FIG. 2) the second piece 2 is picked up by the 
translating element 3. More precisely, the plate 11 of the later is 
brought into contact with the upper surface of the piece 2, which remains 
adherent thereto by virtue of the current circulated in the electromagnets 
21. 
Immediately after said picking up, the piston 13 lifts the plate 11 with 
the piece 2, while the double-acting cylinder 19 is so actuated that its 
stem causes the advancement of the carriage 14, and therefore of the piece 
2, in the sense indicated by the arrow F. Said advancement, which is 
therefore effected in a direction perpendicular to that of the cords C, 
terminates when the initial end E of the piece 2 corresponds to the 
operating part 30 upstream the splicing device 4. 
In this position, the piece 2 is laid on the plane identified by the rows 
of fingers 48, 49, 50 and 51 of the base elements 32 and 33 of the 
splicing device, which plane is preferably not coplanar with the roller 
plane from which the second piece has been taken up, and is situated 
nearly at the same level as the plane along which the second piece moves 
during its positioning stroke. The minimum necessary hollow space only is 
provided between the two surfaces to avoid rubbing of the piece on said 
plane during said stroke. 
The positioning of the piece 2 is obtained by simply disconnecting the 
power supply to the electromagnets 21 of the translating element 3, and 
said positioning is such that the initial and E of said piece is at a 
pre-established distance (indicated by D in FIG. 7) from the terminal end 
U of the first piece 5. 
In said position, the pieces 2 and 5 are perfectly aligned and coplanar. 
At this moment, while the translating element 3 moves away in the direction 
of the arrow F', the two pieces are blocked by lowering the movable 
ledgers 34 and 35 and by inflating the chambers 56 and 57, which bring the 
knurled surfaces of the fingers into engagement with the surfaces of the 
two pieces. 
Also during this blocking, the ends E and U remain coplanar to each other 
and to the respective pieces 2 and 5. 
At this moment, the butt-splicing of the pieces is carried out without 
overlapping. It comprises a first step in which the fluid under pressure 
is sent to the double-acting cylinders 26 in such a way that their bodies 
move in the direction of the arrow F, together with the hollow shaft 28 
and to the operating part 30 of the splicing device, while part 31, fast 
with the hollow shaft 29 and therefore to the shaft 24, remains 
stationary. 
The stroke effected by the hollow shaft 28 is stopped, in the 
pre-established longitudinal position, by the ring nut 27 and is such 
that, at the end of this first step, the condition is that illustrated in 
FIG. 8. As it can be seen, by virtue of the approaching of piece 2 to 
piece 5, a uniform action of accumulation of the rubber of the rubberized 
fabric takes place at a band situated symmetrical astride the surface of 
mutual contact of the ends E and U. The width of said band is 
substantially defined by the mutual position of the knurled surfaces of 
the fingers at the end of said approach and therefore said width is 
proportional to the distance of ends E and U from said knurled surfaces. 
The accumulation of the rubber takes place because the recesses of height 
A, which exist initially around the surfaces of the fingers, are filled by 
the rubber of the rubberized fabric, since the pieces cannot move on the 
plane containing them, because they are blocked by the knurled surfaces of 
the fingers themselves. 
Simultaneously with said accumulation, in the first phase a local 
thickening of the cords C of the pieces takes place at said band. 
This first phase is followed by another phase, typical of the present 
invention, like the first, which provides the detachment of the operating 
part 30 upstream the splicing line from the downstream part 31, in the 
direction of the arrow F', so that the above-described operations are 
repeated in an opposite sense. 
As the rubber of the rubberized fabric is in a plastic condition, it 
returns to the condition it had before splicing at said smooth surfaces of 
the fingers; the same takes place in respect of the thickness of the 
reinforcing metal cords. Of course, the butt-splicing of pieces 2 and 5 at 
their respective initial end E and terminal end U remains unaffected. 
Then the chambers 56 and 57 are deflated and the movable ledgers 34 and 35 
are lifted in order to allow the continuous winding up of the continuous 
band of rubberized fabric provided with transversal reinforcing metal 
cords, on the collecting drum 6, in the length necessary to have the 
terminal end U of the so-called piece 2 positioned in the same position 
which the terminal end U of piece 5 had at the beginning of the cycle. 
The advantages afforded by the here described method and apparatus are 
evident. First of all, there is a perfect alignment of the pieces to be 
spliced together. Said alignment is ensured by the vertical plate 8 and by 
the translating element 3, provided with magnets 21, for picking up and 
positioning the so-called second piece with respect to the so-called first 
piece. 
Secondly, the splicing is carried out in a simple and reliable manner and 
in such a way that, at its end, the surface of the so-obtained continuous 
band of rubberized fabric is appreciably uniform for its whole length, 
even on the above described band situated astride the true splicing 
surface. Therefore the maximum circumferential uniformity of the tire 
carcasses which are built up by using the so formed band of rubberized 
fabric is ensured. 
At last, it is to be pointed out that the herein described method and 
apparatus, in particular the splicing device, do not give the same very 
good results if they are used for splicing two pieces of cord fabric 
reinforced with non-metallic cords. In fact, the latter have a transversal 
rigidity which is much lower than that of the metal, preferably steel 
cords, so that the positioning of the piece is difficult and inaccurate, 
and the splice, in consequence of both causes, is irregular and not 
uniform. 
Conveniently, the present apparatus can be provided with lamps for 
radiation heating the initial end of the so-called second piece up to the 
softening temperature (about 60.degree. C) of the rubber of its rubberized 
fabric, before being picked up by the translating element. In this way the 
butt-splicing of the two pieces is further facilitated. 
Although the present invention has been here described according to a 
particular advantageous embodiment, it is to be understood that the scope 
of protection of said invention includes also all the modifications 
accessible to the technicians of this field derivable from the above 
indicated inventive concept.