WO1992016954A1

WO1992016954A1 - An apparatus for supporting and orientating in a balanced fashion the mandrel on which superconducting wires of elongated shape magnetic coils are wound

Info

Publication number: WO1992016954A1
Application number: PCT/IT1992/000029
Authority: WO
Inventors: Girogio Davini
Original assignee: Ezio Selva S.R.L.
Priority date: 1991-03-14
Filing date: 1992-03-13
Publication date: 1992-10-01
Also published as: ITMI910680A1; IT1245193B; EP0575455A1; ITMI910680A0

Abstract

There is described herein an improved apparatus (1) suitable for supporting and orientating in a balanced fashion the sharply elongated mandrel (3) during winding of superconducting wires for forming magnetic coils. There is provided a number of apparatus for controlling the mandrel (3) orientation, in spaced apart locations along the latter, in order to reduce torsional effects, and a number of supporting apparatus substantially identical to the previous apparatus except for lacking the drive means, in order to reduce bending effects on said mandrel. They are based on the use of positive or shift-free transmissions and of links providing a mechanical parallelogram system for moving the mandrel (3) which, in such a way, may perform a complete rotation, from -90° to +90°, relative to the vertical, without any obstacle from above the mandrel supporting bar (2), which may interfere with the winding of the conducting wire when said mandrel (3) is located in one of the two end positions.

Description

"AN APPARATUS FOR S UPPORT ING AND ORIENTATING IN A BALANCED FASHION THE MANDREL ON WHICH SUPERCONDUCTING

WIRES OF ELONGATED SHAPE MAGNETIC COILS ARE WOUND."

This invention concerns an apparatus suitable for supporting and orientating in a balanced fashion the mandrel for winding superconducting wires in order to form elongated shape magnetic coils, in particular for dipoles and quadrupoles.

Some apparatus are already known for automatically winding coils on a mandrel or coil supporting form, in which coils the conducting or superconducting wires lie predominantly in a longitudinal direction, parallel to the coil center line, with heads having radiuses of variable extent but in any case relatively short. According to what is disclosed for instance in Italian Patent No. 1 202 489, in the name of the Applicant, the form or mandrel is rotatingly mounted for a back and forth motion around an axis which coincides or is parallel to the center line of the coil, within an angle of oscillation of approximately 180° total, on a stationary bedplate having slidingly mounted on a side thereof a reciprocating reel and carriage assembly from which the superconducting wire to be wound on the coil is withdrawn. When winding especially elongated coils used in particular in particle accelerators, to prevent an incorrect formation caused by torsional deformation deriving from the high slenderness factor of a mandrel driven for rotation at a single end thereof, a different drive has been provided compris ing half-ring gears meshing with a drive gear and comprising three sectors among which the outer ones are pivotally connected to a center sector, whereby when the mandrel integrally fastened to said half-ring gears is vertical, the engagement between the drive gear and the half-ring gears takes place in a central area thereof at a stationary guide shaped as an arc of a circle, while when the mandrel lies in a tilted position on one side or the other a branch of each half-ring gear will have rolled downwards by rotating around a respective pivot, in order to allow the conducting wire an unhindered access to the mandrel side now facing upwards due to the mandrel tilting motion. The above is an essential condition for the apparatus to operate correctly when a drive arrangement of this kind is provided not only at the ends of the mandrel and of the support bar thereof, but also in intermediate positions, as it is the case when positively trying to reduce the torsion and flexure effects.

However, it has been found that the rolling over of the outer branches of the half-ring gears does not provide for a complete absence of obstacles which may interfere with the correct winding of the conducting wire which has to be carried out with the highest precision in order to provide defect-free coils.

Therefore, it is an object of this invention to provide an apparatus adapted to perform as a supporting and/or handling means suitable for being mounted in a number of units at equally spaced positions along the length of the mandrel, for the purpose of reducing the bending and torsion effects while simultaneously allowing the mandrel to perform a complete 180° arc oscillation in order to reach the two horizontally opposed end positions, with no hindrances or interferences, namely from above, while the mandrel is left absolutely free in space except for the supporting bar thereof, or connecting arm between said mandrel and the apparatus.

According to this invention, the above object is met by using links and positive or shift-free drive means similar to a mechanical parallelogram system. It may be assumed that for a mandrel 8 to 20 meters long a suitable number of units to be used is two-three drive and orientation apparatus and two to ten support apparatus, taking into account that the latter are substantially identical to the former, except for the missing drive means.

Preferably in order to balance the moments of the forces generated by the weight of said mandrel and of the winding thereon, all the apparatus will be provided with balancing devices based on using a pneumatic cylinder slidingly mounted on. a guide and having a piston rod providing the support for one of the pivots of said mechanical parallelogram.

The above and other objects, advantages and features of the apparatus according to this invention will become more apparent from the following detailed description of a preferred embodiment thereof, shown herein for exemplary and not limiting purposes, referring to the attached drawings wherein:

FIGURE 1 shows a schematic view of the supporting and orientation apparatus, at a mandrel horizontal position, or oscillation limit position thereof;

FIGURE 2 shows a view similar to Figure 1, for the mandrel located in an intermediate tilted position;

FIGURE 3 shows a side view, partially in cross section, of the construction of said apparatus, taken in a plane perpendicular to that of the above Figures; and

FIGURE 4 shows another schematic of the apparatus, similar to Figure 1, including a balancing device.

Reffering now to the drawings, Figures 1, 2 and 4 are all schematic representations of orientating and supporting apparatus 1 according to this invention, and they are all taken in a section plane transverse to the longitudinal direction of typically U-shaped mandrel 3 suitable for winding a superconducting wire coil thereon, mounted on a longitudinal support bar 2 which is in turn fastened in at least two positions at the ends of the coil winding machine, but more preferably supported in a number of locations equally spaced along the length thereof, each time on a spindle member 31 whose axis 19 provides the back and forth oscillating pivot, according to the direction of arrow F, of the assembly comprised of mandrel 3 and bar 2. Referring now to Figure 3, there is shown therein the way bar 2 may be fastened to spindle 31, for instance by means of bolts 5. At the opposite end of spindle 31 there is mounted a pinion gear 30 which is connected, by means of a positive or shift-free transmission member 24 formed for instance of a chain or cog belt, to a second pinion gear 28 mounted on a spindle 29, parallel to spindle 31. on the latter there is also free-rotatingly mounted the end of a link 14, whose opposite end is free to rotate around said spindle 29, whereby the connection between the pair of spindles 29 and 31 is double, both by means of transmission 24 and through link 14 whose center line is shown at 21 in Figures 1, 2 and 4.

In a similar fashion, spindle 29 as well is connected to a third spindle 27 both by means of a transmission member 25, the latter too being positive or shift-free, and by means of a link 13. On spindle 29 there is in fact mounted a freely rotating pinion gear 32 integral with link 14 meshed with chain or cog belt 25 whose opposite end is in meshing engagement with pinion gear 26 coaxial with said spindle 27 and fastened on the machine frame or support structure, schematically shown at 23 in the drawings. Therefore, spindle 27 takes a fixed position in space, contrary to the other two spindles 29 and 31 which, as shown in Figures 1 and 2, are displaced according to the tilting angle of mandrel 3 relative to the horizontal direction. Up to this point there has been described above what may be called a simple mandrel supporting apparatus, which is adapted to follow the latter while oscillating along a ± 90° angle relative to the vertical balance position shown in Figure 3. As it is shown therein, in said position, all the transmission means, i.e. both the links 13 and 14, and the cog belts 24 and 25, are aligned in such a way that they would be shown overlapping each other in a view similar to Figure 2. It may be seen as well that both assemblies comprising link 14/transmission member 24, with center line 21, and link 13/transmission member 25, with center line 20 thereof, respectively, are similar to mechanical parallelograms, which provide a correct positioning of the assembly so that the latter conforms to the positions taken in turn by mandrel 3.

Up to this point there has been described the supporting apparatus, which may be provided in a number of locations along the length of the mandrel. In order to drive the oscillating motion of mandrel 3, the orientating apparatus, as they were called previously, are as well in a number of at least two, at the ends of the machine, and preferably also in a larger number, for instance with a third one at half the mandrel length, each one of them including the members already described previously for support only. Referring to the drawings, for the orientating function, link 13 is rotated under external drive, for instance by means of a pinion gear 33 freely rotatable around stationary spindle 27, and set in motion by a transmission member 36 (still comprising a chain or a shift-free cog belt) which is meshing engagement with a pinion gear 35 at the output shaft of a gear motor or D.C. current motor 34. It should be noted that the shift-free arrangement is necessary in order to be able to positively determine the tilting angles of mandrel 3 and to provide a numerically controlled type motor 34.

As it is shownin the Figures, there is shown at 22 the center line of structure 23 on which spindle 27 is mounted, said center line being coincident with the line connecting the center line of the spindle with mandrel center line 7. It should be noticed that center line 21 is kept constantly parallel to the latter, independent upon mandrel 3 tilting angle, while transverse center line 4 of said mandrel, passing through pivot center 19, is kept constantly parallel to center Line 20, by the double mechanical parallelogram system, as it is assured by transmission members 24 and 25 respectively. The rotations of mandrel 3 take place around the longitudinal center line 7 which is kept constantly in a stationary position in space.

Referring now to Figure 4, there is shown sche¬matically therein the complete apparatus provided with the balancing device 6 whose purpose is to reduce the torsional actions within the mandrel, which may easily take place since the latter is a long member which, in some cases, may reach 20 meters of length, in the same way as support bar 2 thereof. A balancing device 6 is provided for all the apparatus 1, both the simply supporting and the orientating ones. In Figure 4 the mandrel, and therefore the supporting and orientating apparatus 1, are shown in a limit position, completely tilted to the left, and with the transverse center line 4 in a horizontal position, and angle α equal zero. As it should be apparent, orientating device 1 may proceed to any one of a number of positions, going from the one shown herein to the one located 180° apart, through a rotation according to arrow F.

As it should be noted, mandrel 3 is non-symmetrical relative to axis 8, whereby center of gravity 9 is diplaced relative to rotation center line 7. Force F₁ applied at 9 generates a moment M₁ which is variable according to angle α formed by transverse center line 4 with the horizontal direction. The maximum value of moment M₁ tending to rotate the mandrel clockwise is generated when the latter is in a horizontal position to the right, and it progressively decreases down to zero when the mandrel is in a vertical position, and it reaches a maximum in a counterclockwise direction when the mandrel is in a horizontal position to the Left. The purpose of balancing device 6 is to balance said moment M₁ with an equal and opposite moment M₂.

It includes a pneumatic cylinder 10 whose piston rod is fastened to the pivot point between Link 13 and Link 14, in practice at the position of center line 12 of spindle 29, while body 15 of the cylinder is mounted on a sledge basis 16, adapted to slide on a guide 17. Compressed air supply A is in communication with the lower chamber of cylinder 15, underlying piston 11a, through a valve 18 which provides a constant pressure of the air supplied while the volume of said Lower chamber changes. Force F₂ generated by cylinder 10 is applied to pivot point 12 in a direction constantly normal to guide 17, so that a moment M₂ is generated relative to link arm 13. If the legth of Link 13, i.e. the distance between pivot center 12 and the center Line of spindle 27 is made equal to the distance between pivot point 19 and mandrel center line 7, and if force F₂ as well as is controlled through the setting of valve 18, so that F₁ = F₂, also moment M₂ will be equal to M₁ and opposite in direction due to the opposite directions of forces F₁ and F₂, so that a perfect balance of the system is provided. The setting of valve 18 will be controlled in such a way that, while winding the coil, account is taken of the increasing weight of the conducting wire on mandrel 3. Simultaneously, cylinder 10 will slide back and forth on guide 17 in order to keep piston rod 11 vertically in contact with pivot 12.

The operation of the apparatus according to this invention should be apparent from the above description. Numerically controlled motor 34 rotates pinion gear 35 at a predetermined speed and for set periods of time, said pinion gear causing a corresponding rotation of pinion gear 33 and therefore, through link 13, spindle 29 is rotated in space along a corre¬sponding arc of a circle while pinion gear 32 as well is rotated around its axis by transmission 25. Therefo¬re, link 14 as well is rotated around pivot 12, together with pinion gear 28 integrally fastened to link 13, which pinion gear caused rotation of pinion gear 30 mounted on spindle 31, through transmission means 24. On said spindle there is fastened support bar 2, which sets in rotation therewith the transverse axis 4 of mandrel 3, while keeping point 7 in a stationary position in space, as one of the corners of a parallelogram whose second stationary corner is the center line of spindle 27, while the two moving corners are center line 19 of spindle 31 and center line 12 of spindle 29. Further conditions for providing said mechanical parallelogram will then be an equal length of link 13 and of the distance between pivot point 19 and the center line 7 of the mandrel and an equal length of link 14 and of the distance between spindle 27 and still said center line 7. For each apparatus, either supporting only or generating a simultaneous orientating action, there is provided a balancing device, as described above, which by independently moving while the position in space of spindle 29 changes, in order to keep the orthogonality of force F₂ generated in an upwards direction by piston rod 11, in every moment cancels, with an equal and opposite moment M₂ the moment M₁ caused by the mandrel eccentricity.

Possible additions and/or modifications may be made by those skilled in the art to the embodiment of the apparatus according to this invention, shown and described above, without exceeding the scope of said invention. In particular the transmission means may be embodied in a way different from the one shown and described herein, provided the requirement of perfect positive or shift-free engagement is maintained.

Claims

C LA I MS

1. An apparatus for supporting and orientating the mandrel (3) for winding superconducting wires of elongated shape magnetic coils, wherein said mandrel (3) is mounted on a support bar (2) having a length substantially equal to the mandrel length, and comprising a support frame (23) whereon said bar (2) is rotatingly supported around a centerline (7) stationary in space, in order to provide back and forth oscillation of mandrel (3) along approximately a plus or minus 90° angle relative to a vertical central position, there being provided a motor (34) adapted to cause said oscillating motion, characterized in that said center line (7) and the centerline, parallel thereto, of a spindle (27) mounted stationary on said frame (23) provide the stationary corners of a linking parallelogram whose three further sides defining the moving corners comprise respectively said mandrel (3) and supporting bar (2) thereof having a centerline (4), transmission means (14, 24) comprised between a spindle (31), with centerline (19) parallel to said centerline (7) and having said support bar (2) mounted thereon, and a second moving spindle (29) having a centerline (12), as well as transmission means (13, 25) between said spindle (29) and said stationary spindle (27).

2. The apparatus of claim 1, characterized in that said transmission means comprises Links (13, 14) and' chains or shift-free cog belts (24, 25) wherein means (24) meshes with a pinion gear (30) on spindle (31) and with a pinion gear (38) of spindle (29), and respectively means (25) meshes with a pinion gear (32) on spindle (29) and with a pinion gear (26) on spindle (27).

3. The apparatus of claim 1 or 2, characterized in that, for the purpose of orientating mandrel (3), on said spindle (27) there is mounted freely rotatable a pinion gear (33) integrally fastened to said link (13) and connected to said motor (34) through a positive or shift-free transmission member (36) further meshing with a pinion (35) at the output of said motor (34).

4. The apparatus according to one or more of the previous claims, characterized in that the length of said link (13) is equal to the distance between said centerline (7) of rotation of said mandrel (3) and said centerline (19) of spindle (31), and in that the length of said link (14) is equal to the distance between said centerline (7) and the centerline of said spindle (27).

5. The apparatus of claim 3, characterized in that said link (13) is kept parallel to said transverse centerline (4) of mandrel (3) while the tilting angle of the latter changes and said link (14) keeps a position parallel to line (22) connecting said mandrel center line (7) with the centerline of said spindle (27).

6. The apparatus according to claim 4, characterized in that it further includes a balancing device (6) comprising a piston and cylinder assembly (10) slidingly mounted in a sledge-like fashion on a guide (17) integral with the machine bed-plate, and wherein piston rod (11) transmits an upwardly directed force to the axis (12) of said spindle (29), said force (F₂) being equal to the weight (F₁) of the mandrel and related coil, applied at the center of gravity (9) of said mandrel, spaced apart from the axis of rotation (7), thereby causing a moment of forces and opposite to the one generated by weight (F₁) and balancing the same, owing to the arms, at which forces (F₁, F₂) are applied, having the same length.

7. The apparatus of claim 6, characterized in that said piston-cylinder assembly (10) is supplied with compressed air through a controllable valve (18) in order to keep said force (F₂) constant, or in any case equal to the value of (F₁) variable during the winding operations, for different values of the useful volume of cylinder (10) as a consequence of changes of the height of said centerline (12) while mandrel (3) osci Hates.

8. An apparatus for supporting and orientating in a balanced fashion the mandrel for winding super¬conducting wires of elongated shape magnetic coils, substantially as shown and described above.