WO1997032316A1

WO1997032316A1 - Transposing apparatus for the manufacture of c.t.c. conductors

Info

Publication number: WO1997032316A1
Application number: PCT/EP1997/000953
Authority: WO
Inventors: Marino Ozino
Original assignee: Proteco Di Cappa Rasone Edda & C. S.A.S.
Priority date: 1996-02-28
Filing date: 1997-02-27
Publication date: 1997-09-04
Also published as: AU1924297A; ITTO960142A0; ITTO960142A1; IT1285274B1

Abstract

A transposing apparatus (T) for the manufacture of C.T.C. conductors formed by two adjacent stacks (C1, C2) of multiple conductive strips (P1, P2) superimposed to one another and continuously transposed from one stack to the other. The apparatus (T) comprises a first and a second pair of pressure rotors (26) and of reaction and shift rotors (27) arranged at the bottom and at the top, respectively, of the two stacks, with the rotors of one pair reversed with respect to the rotors of the other pair. The rotors (26, 27) are counter-rotated in a synchronized and pulsed fashion and are each bearing a respective eccentric idle roller (32, 33) laterally contacting the conductive strips. The reaction and shift rotors (27) are provided with respective axial cams (34) for raising and lowering the respective stacks (C1, C2), and a thrust member (37) is operatively associated to each pressure rotor (26) to enhance the shifting action on the stack (C1, C2) operated by the corresponding reaction and shifting rotor (27).

Description

"Transposing apparatus for the manufacture of C.T.C. conductors''

***

Field of the invention

The present invention is related to the manufacture of C.T.C. conductors ("Continuously Transposed Conductors").

State of the prior art

As it is known, these C.T.C. conductors are constituted by quadrangularly outlined strands formed by two adjacent stacks of superimposed multiple conductive strips, the size and number of which are variable as a function of the destination of use of the conductor, and having a quadrangular cross-section. Manufacturing of such conductors traditionally involves revolution motion of the conductive strips wound on reels, performed by means of a rotary detorsion cage, longitudinal entrainement of the conductive strips so as to build up the two stacks, and passing on the two stacks through a transposing apparatus at which plastic bending deformation means operate continuos transposing of the conductive strips from one stack to the other, according to a frequency which is synchronized with the revolution movement of the conductive strips being unwound by the rotary cage, and also depending upon the number of these strips. Shifting means displace the two stacks in opposite directions, normally one stack upwardly and the other stack downwardly, in a synchronized fashion with the transposing deformation, perpendicularly to the longitudinal travel direction of the conductive strips. The plastic deformation means perform transposing of the conductive strips, each time placed at one end of each stack, onto the corresponding end of the other stack. In other words, the conductive strip placed on top of the first stack is laterally deformed so as to be displaced on top of the second stack, and the conductive strip placed at the bottom of the second stack is laterally deformed onto the bottom of the first stack, while the two stacks are moved upwardly and downwardly, respectively, over a distance corresponding to the height of a conductive strip.

From GB-B-969.086 a transposing head for the manufacture of C.T.C. conductors is known, wherein the plastic deformation means and the shifting means are comprised of two pairs of juxtaposed slidable press tools, which are driven through respective cam actuators in turn operated by four shafts rotated by a peripheral toothed annular gear wheel.

From DE-A-3923448 a similar transposing head for the manufacture of C.T.C. conductors is also known, in which a counter-mould is associated to each slidable press member, so as to improve bending precision of the conductive strips being transposed.

These known transposing systems are affected by several drawbacks.

Firstly, the plastic deformation systems of the known transposing heads carry out transposing bending over a relatively great length of the conductive strips, and consequently a relatively short distance between successive bendings of the conductive strips, which involves worsening of the winding capability of the C.T.C. conductor at the outlet of the transposing head. Several applications require a reduced winding diameter, which evidently cannot be achieved with the conventional transposing systems.

A further incovenience of the prior art resides in a limited production speed and in the practical impossibility of quickly adjusting and adapting the transposing apparatus to conductive strips having different sizes and/or to stacks having a different number of conductive strips. Actually, in this case adapting the line involves as a rule replacement of at least part of the operative components of the transposing apparatus, thus requiring long production stops.

Statement of the invention

The primary object of the present invention is to provide a transposing apparatus for the manufacture of C.T.C. conductors enabling to appreciably reduce both the transposing length (l_t) and the transposing pitch (p_t) of the conductive strips, so has to provide shorter winding diameters of the transposed conductors.

A further object of the invention is to increase the transposing process speed, and thus the production rate of the manufacturing line as a whole.

Another object of the invention is to increase transposing reliability and repeatability, even in the case of conductive strips having reduced size as well as of stacks having a greater number of conductive strips.

Still a further object of the invention is to provide a transposing apparatus which can be easily and quickly adapted to relatively wide size and number (even or odd) ranges of conductive strips of the two stacks.

In view to achieve the above objects, the present invention is directed to a transposing apparatus the main features of which are set forth in claim 1. Additional secondary features of the transposing apparatus according to the invention are recited in sub-claims 2 through 16.

Brief description of the drawings

The invention will now be disclosed in detail with reference to the accompanying drawings, purely provided by way of non-limiting example, in which: - figure 1 is a diagrammatic perspective view of an example of C.T.C. conductor manufactured according to the invention,

- figure 2 is a top plan and reduced view of the C.T.C. conductor shown in figure 1,

- figure 3 is a diagrammatic lateral elevational view of a line for the manufacturing of C.T.C. conductors including a transposing apparatus according to the invention,

- figure 4 is a fragmentary and simplified partially vertically sectioned view of an apparatus equipped with the transposing apparatus according to the invention,

- figure 5 is a partially horizontally sectioned view of the transposing apparatus along line A-A of figure 4,

- figure 6 shows in an enlarged scale a detail of figure 4,

- figure 7 is a partially horizontally sectioned view along line D-D of figure 6,

- figure 8 is a diagrammatic and simplified perspective view from above of figure 7, in a first operative condition,

- figure 9 is a view same as figure 8 showing a second operative condition,

- figure 10 shows diagrammatically and in an enlarged scale a part of figure 4, namely the formation area of the C.T.C. conductor, with reference to a first step of the forming cycle,

- figure 11 is a horizontally sectioned view along line B-B of figure 10,

- figures 12, 14, 16, 18 and 20 are views same as figure 10 showing the subsequent steps of the forming cycle,

- figures 13, 15, 17, 19, 21 are views same as figure 11 during the steps corresponding to figures 12, 14, 16, 18 and 20, respectively, - figures 22, 23 and 24 are views same as figure 11 showing a peculiar aspect of the invention during the formation cycle,

- figure 25 is a view same as figure 7, but in more detail, partially sectioned, in an enlarged scale and partially modified,

- figure 26 is a vertically sectioned view along line C-C of figure 25,

- figure 27 shows a first variant of figure 7, and

- figure 28 shows a second variant of figure 7.

Detailed descriptions of preferred embodiments of the invention

Figures 1 and 2 show one example of a C.T.C. conductor such as manufactured by means of a transposing apparatus according to the invention. This conductor, generally designated by reference C, is formed by two parallel and side-by-side stacks Cl, C2 of superimposed multiple conductive strips PI, P2 (in an even or odd number), each of which is continuously transposed from one stack to the other following a plastic bending deformation, in the way clarified herebelow.

The size of the conductive strips PI, P2 and the number of these strips in each stacks Cl, C2 can be widely varied as a function of the final use of the conductor. A significant parameter related to the C.T.C. conductor geometry consists of the ratio between the transposing length (l_t) and the transposing pitch (p_t): this parameter is indicative of the winding capability of the conductor into reduced diameters. The invention provides transposing length (l_t) and transposing pitch (p_t) of the strips PI, P2 remarkably reduced as compared to the prior art, and, accordingly, a remarkable reduction of the winding diameter of the conductor C.

Moreover, the invention allows the transposing length to be adjusted, as well as conductive strips PI, P2 of different sizes and/or different number (even or odd) to be employed, following simple and prompt adjustments.

Figure 3 diagrammatically depicts a C.T.C. conductor forming line, comprising in a generally conventional way a multi-reel detorsion rotary cage G for the conductive strips PI, P2 supplying, via a synchronizer unit, a motor- driven transposing apparatus T according to the invention. The transposed conductor C exiting from the transposing apparatus T is wound, downstream of a taping assembly N applying thereon an insulating covering and through a haull off device R, onto a take-up drum A.

The transposing apparatus T is generally shown in better detail in figures 4 and 5. It comprises a base 1 bearing a vertical support structure 3 which carries two superimposed transposing assemblies 4 and 5 adapted to be vertically moved towards and away relative to each other. Vertical displacement of the two transposing assemblies 4, 5, to the aim of adjusting the apparatus T to forming transposed conductors C including a greater or lower number of strips PI, P2, is performed by slidably mounting these assemblies 4, 5 along vertical guides 6 of the support 3 and through a manually-operable or motor-driven system, for instance of the screw and nut type generally indicated as 7, possibly with an associated manually operated fine adjustment system, not shown in the drawings since generally conventional.

Rearward of the support 3, the base 1 bears a motor 8 with associated encoder 9 which operates, through a transmission 10, 11, a pair of input shafts 12, 13 in turn operating respective output shafts 14, 15 through respective jogging devices 16, 17. These jogging devices 16, 17, not shown in detail since of a conventional type, transform continuos rotation of the input shafts 12 and 13 into corresponding intermittent rotations of the output shafts 14 and 15.

The transmission 10, il and the jogging devices 16, 17 are designed to normally drive in a pulsed and synchronized fashion the output shafts 14 and 15 simultaneously or, through a kinematic system of a conventional type, alternatively. The different operating system may be switched, for instance by means of a manually operable selector 43, depending upon the number of strips which form the two stacks of the transposed conductor C being even or odd, respectively.

The output shafts 14, 15 are coaxially connected to respective drive shafts 20, 21 of the two transposing assemblies 5, 4.

The arrangement of the transposing assembly 4 will now be disclosed, taking into account that the arrangement of the transposing assembly 5 is almost identical, but for the differences which shall be further clarified.

Referring in better detail to figure 6, the drive shaft 21 operates, through a transmission unit 22 and a gear box 23, two vertical counter-rotating shafts 24, 25 to which a first and a second rotor 26, 27 are coupled in rotation, whose axis are indicated as 28, 29, respectively.

As also shown in detail in figures 7, 8, 9 and 25, the upper faces of the rotors 26 and 27 are arranged flush with a bearing surface 30 over which the strips PI, P2 advancing from the detorsion cage G are slidably traveling. The axis 28, 29 of the rotors 26, 27 are offset relative to each other along the longitudinal traveling direction of the strips, indicated by arrow F in figures 5 and 7, and the mutual positioning thereof along such direction F can be adjusted. Accordingly, the rotor 27 may for instance be displaced along a slot 31 provided in the surface 30 (as better shown in figures 5 and 7), or this surface 30 may be formed by two distinct and separate portions 30a, 30b, of which one bears the rotor 26 and the other bears the rotor 27 and whose mutual distance can be varied simply by the interposition of gauged spacers 30c therebetween, as shown in figure 25.

The rotor 26 is designated as "pressure rotor" since, as it will be apparent in the following, its function is to transpose the strip PI, each time placed at the bottom of the stack Cl, to the bottom of the other stack C2. The rotor 27, designated as "reaction and shifting rotor" has a twofold function consisting on one hand to act as a reaction member for the transposing deformation of the strips PI performed by the pressure roller 26, and on the other hand to shift the stack C2 upwardly so as to allow location at the bottom thereof of the strip Pi each time transposed.

Both rotors 26 and 27 are superiorly provided with respective eccentric rollers 32, 33 acting as a pressure member and as a reaction member, respectively, performing a lateral rolling contact against the flanks of each strip during the transposing step.

Moreover, the rotor 27 is formed superiorly with a rising-ramp angular portion 34 acting as a bearing and lifting surface of the stack C2. It is to be pointed out that the rising-ramp portion 34 could be formed in the lower instead of in the upper face of the rotor 27, and in this case this rotor 27 would be supported on the surface 30 in a vertically-displaceable way along its axis. In either case an adjustment and/or resilient device might also be provided in connection with the support system of the rotor 27.

Upstream and downstream of the rotors 26, 27 with respect to the traveling direction F of the strips, the surface 30 is provided with respective line-up assemblies 35, 36 for the strips PI, P2 at the inlet, and of the transposed conductor C at the outlet of the transposing assembly 4, respectively. These line-up assemblies 35, 36 may be comprised of idle rollers or simply by stationary members (as shown in figures 8 and 9), or still by combination of rollers and stationary. In any case positioning of the line up assemblies 35, 36 can be adjusted by means of conventional systems not shown in detail. Referring now particularly to figures 8, 9 and 25, 26, to the aim of enhancing and extending the upwardly shifting action of the strip stack operated by rotor 27, a resilient thrust member, acting from below against the bottom of the stack C2, is operatively associated to the rotor 26. This resilient thrust member is constituted by a springing shaped arm 37 vertically movable through an aperture 40 of the surface 30 and carried by a rocker lever 41 which is pivotally supported at 42 and is driven by the rotor 26 through a cam mechanism 38. Upon rotation of the rotor 26, the arm 37 is raised by the lever 41 so as to push upwardly the stack C2 , and during transposing of the strips PI this arm 37 is elastically displaced laterally thereby, such as depicted in figure 9 and with dotted lines in figure 26, thus returning into its initial lowered position.

Reverting now to figure 6, the shaft 24 operating rotation of the rotor 26 may be provided with a resilient torsional device 39, of a generally conventional type and thus not depicted in detail, the function of which is to make the angular thrust action of the roller 32, during the transposing steps, progressive. Operation of the resilient device 39 shall be further clarified in the following.

As already previously pointed out, the arrangement of the transposing assembly 5 is same as that of the above disclosed assembly 4, with the only difference related to the fact that the respective rotors 26, 27 are facing downwardly and reversed with respect to the rotors 26 and 27 of the assembly 4. In other words, the pressure rotor 26 of the assembly 4 is located on the side of the reaction and shifting rotor 27 of the assembly 5, and the pressure rotor 26 of the assembly 5 is located on the side of the reaction and shifting rotor 27 of the assembly 4. Evidently, with this arrangement the pressure rotor 26 of the assembly 5 performs transposing of the strip P2 each time placed on top of the stack C2 towards the top of the stack Cl, and the rotor 27 of this assembly 5 operates each time downward displacement of the stack Cl so as to enable this transposing.

As also already clarified in the above, the pulsed driving of the rotors 26, 27 of the two assemblies 4 and 5 may be operated simultaneously, in case the number of strips of the two stacks is even, or alternatively, in case this number is odd.

Referring now to figures 10 through 21, the operation cycle of the transposing apparatus T will now be disclosed in further detail, with specific reference to the stacks Cl, C2 being comprised of an even number of strips PI, P2. In the case of odd number of strips, the rotors 26, 27 would be operatively offset of half a cycle relative to each other.

Briefly, the functional principle is as follows: the two rotors 26 and 27 of the assembly 4 are rotated in synchronism and in opposite angular directions. The two stacks Cl, C2 of strips PI, P2 are freely slidable along the surface 30, and thus over the upper faces of the rotors

26 and 27. The strip PI each time located at the bottom of the stack Cl is deformed and transposed, by virtue of the interaction with and between the rollers 32 and 33, into the space made available at the bottom of the stack C2 following lifting thereof operated by the rising ramp 34 of the roller 37, with the aid of the springing arm 37. Operation of the transposing assembly 5 is identical and opposite in the sense that, as already previously clarified, the respective pressure rotor 26 performs transposing of the strip P2 each time located on top of the stack C2 towards the space made available on top of the stack Cl, following lowering thereof operated by the rotor

27 of the assembly 5 under the cooperation of the springing arm 37 of the respective rotor 26.

In more detail, it is assumed starting from the initial condition shown in figures 10 and 11: the two stacks Cl, C2 of strips PI, P2 are being advanced since drawn by the take up device of the line; the upper and lower pressure and reaction-shifting rotors 26, 27 start rotating, in the directions indicated by the respective arrows.

In the following step (figures 12 and 13) the axial cams defined by the rising ramps 34 of the reaction- shifting rotors 27 begin to vertically displace the respective strip stacks, upwardly as far as the lower rotor 27 is concerned, and downwardly as far as the upper rotor 27 is concerned, such as depicted by the respective arrows.

Then (figures 14 and 15) the pressure rotors 26 start bending of the corresponding strips by displacing them, with reference to the figures, the upper one to the left and the lower one to the right. The idle rollers 32 and 33 of the rotors 26 and 27 remarkably reduce friction between these rotors and the strips.

In the following step (figures 16 and 17) the rotors have covered a rotation angle of 270° and bending of the strips has been completely performed. The distance between the axis of the two rotors 26, 27 of each pair, which as explained can be adjusted, determines the desired transposing length.

Then (figures 18 and 19) the rotors complete their revolution and stop in the start position. The peripheral speed of the rotors, which is considerably higher then the linear speed of the strips, provides a prompt release of the transposed strips which can thus proceed advancing undisturbed.

Subsequently (figures 20 and 21) the rotors remain stationary during a time corresponding to that lapsed during operative revolution thereof, while the strips continue advancing at a constant speed. Thereafter the cycle starts again from the initial step (figures 10 and 11).

Figures 22 through 24 clarify the functional effect of the resilient torsional device 39 associated to each pressure rotor 26. Upon start of the transposing cycle (figure 22) the upper and lower pressure and reaction- shifting rotors 26, 27 start rotating. As soon (figure 23) as the axial cams 34 of the reaction-shifting rotors 27 have displaced the two stacks Cl, C2 upwardly and downwardly, respectively, the respective pressure rotors 27 came into contact, through their rollers 32, with the corresponding strips and elastically yeld angularly owing to resiliency of the torsion devices 39. They start thus to carry out bending of the strips progressively, so as to prevent damaging the flanks thereof.

Then (figure 24) the pressure rotors 26, once having completed transposing of the respective strips, can recover resilient torsional yelding of the corresponding devices 39, most promptly (i.e. following a sudden snap motion) releasing the contact point between the rollers 32 and the strips.

It will be apparent from the foregoing that the transposing apparatus T according to the invention is capable of performing the transposing operation in a quite short time, so as to reduce the strip length interested thereby and limit any geometrical imperfections related to simultaneous advancement and bending. The apparatus according to the invention is completely open, since operation takes place in the space delimited by the two transposing assemblies 4, 5 which are completely separated from each other. This arrangement enables unloading from the transposing apparatus the C.T.C. conductors thus formed without the need of cuttings.

On the other hand, the rolling contact between the rotors and the strips reduces friction therebetween and limits any possibility of scoring or damaging the strips themselves. Lastly, the torsional spring devices associated to the shaft of the pressure rotors make the pushing action of the respective contact rollers gradual, thus preventing impact deformations along the strip flanks.

Naturally the details of construction and the embodiments may be widely varied with respect to what has been disclosed and illustrated, without thereby departing from the scope of the present invention, such as defined in the appended claims. Thus, for instance, the two rotors 26, 27 may have a different diameter, and one or each rotor 26, 27 could even be replaced by a rotating or reciprocating arm. This embodiment is diagrammatically depicted in figure 27, wherein the reaction and shifting rotor 27 is formed as a swinging lever carrying the roller 33 and operated through a crank mechanism generally indicated as 44. The swinging lever 27 is pivoted at 45 to a block 46 which may be vertically displaceable relative to the surface 30, for instance by means of a cam device 47 also operated through the crank mechanism 44, thus performing the same function as the rising ramp 34 previously disclosed.

Further, the curvature radius of one or each rotor 26, 27 may be variable or even infinite: in the latter case the or each rotor shall actually be replaced by a slider. This embodiment is diagrammatically shown in figure 28, wherein the reaction and shifting rotor 27 is formed as a slider carrying the roller 33 and reciprocated through a crank mechanism, also generally indicated as 44, so as to move towards and away from the pressure rotor 26 parallelly to the travel direction F of the conductive strips. The slider 27 is displaceable along a block 48 which in turn may be vertically movable relative to the surface 30, for instance by means of a cam device 49 also operated through the crank mechanism 44 and along guide members 50, thus again performing the same function as the rising ramp 34 previously disclosed.

Lastly, the two rotors 26, 27 could be driven by a stepped motor provided with a control system adapted to adjust the angular speed of the rotors as a function of the travel speed of the conductive strips.

Claims

1. Transposing apparatus (T) for the manufacture of C.T.C. conductors comprised of two adjacent stacks (Cl, C2) of multiple conductive strips (PI, P2) superimposed to one another and continuously transposed from one stack to the other, including a body (4, 5) defining a path through which the two stacks are advanced along a longitudinal travel direction (F), plastic deformation means (26, 27) arranged on opposite sides with respect to said path to perform transposing bending of the conductive strips, each time placed at one end of each stack, onto the corresponding end of the other stack, and shifting means (27) of the two stacks in opposite directions perpendicularly to said longitudinal travel direction (F) and in synchronism with said deformation means (26, 27), characterized in that said deformation means and said shifting means comprise a first and a second pair of rotors (26, 27) arranged at the bottom (4) and at the top (5), respectively, of the two stacks (Cl, C2) of conductive strips (PI, P2) and having their axis (28, 29) oriented perpendicularly to said longitudinal travel direction (F), each rotor pair including a conductive strip pressure rotor (26) and a conductive strip reaction and stack shifting rotor (27), the rotors of each pair being reversed with respect to the rotors of the other pair, and said rotors (26, 27) being counter-rotated in a synchronized way.

2. Apparatus according to claim 1, characterized in that a pulsed drive jogging system (11, 16, 17) is provided for operating counter-rotation of said rotors (26, 27).

3. Apparatus according to claim 1, characterized in that said pressure rotors (26) and said reaction and shifting rotors (27) perform a lateral rolling contact (32, 33) with the conductive strips (PI, P2) .

4. Apparatus according to claim 3, characterized in that each rotor (26, 27) is provided with a respective idle eccentric roller (32, 33) for laterally contacting said conductive strips.

5. Apparatus according to claim 1, characterized in that axial cam means (34) are associated to each reaction and shifting rotor (27) to displace the respective stack (Cl, C2) perpendicularly to said longitudinal travel direction (F) .

6. Apparatus according to claim 5, characterized in that said axial cam means comprise a bearing angular portion of each reaction and shifting rotor (27) formed as a rising ramp (34).

7. Apparatus according to claim 4, characterized in that a resilient torsional device (39) is provided for operating each pressure rotor (26) so as to make the angular thrust action of the respective idle roller (32) progressive.

8. Apparatus according to claim 1, characterized in that a thrust member (37) is operatively associated to each pressure rotor (26) to enhance the shifting action on the stack (Cl, C2) operated by the corresponding reaction and shifting rotor (27).

9. Apparatus according to claim 8, characterized in that said thrust member comprises a resiliently laterally displaceable arm (37) and cam means (38) driven upon rotation of said pressure rotor (26) to operate lifting of said thrust arm (37).

10. Apparatus according to claim 1, characterized in that it further comprises means for adjusting the distance between the rotation axis (28, 29) of the rotors (26, 27) of each pair along said longitudinal travel direction (F).

11. Apparatus according to claim 1, characterized in that it further comprises means (6, 7) for adjusting the distance between said two rotor pairs (26, 27) as a function of the height of said stacks (Cl, C2).

12. Apparatus according to claim 11, characterized in that said pairs of rotors (26, 27) are carried by respective units (4, 5) born by a support structure (3) in a vertically displaceable way towards and away from each other.

13. Apparatus according to claim 1, characterized in that it further comprises rotary or stationary guide members (35, 36) for aligning said two stacks (Cl, C2), arranged on opposite sides thereof and upstream and downstream of said rotors (26, 27) with respect to said longitudinal travel direction (F) of said stacks (Cl, C2).

14. Apparatus according to claim 2, characterized in that said pulsed operating system (11, 16, 17) is selectively switσhable between simultaneous or, respectively, alternative driving of said two pairs of rotors (26, 27).

15. Apparatus according to any of claims 1-5, characterized in that at least one of said rotors (26, 27) is replaced by a swinging lever.

16. Apparatus according to any of claims 1-5, characterized in that at least one of said rotors (26, 27) is replaced by a slider.