A flywinder

Description

Technical field

[0001] The invention relates to an apparatus for winding filamentary material, particularly wire, on a bobbin.

Background art

[0002] A technique generally known as "fly winding" is presently available for wrapping wire around a stationary bobbin and the technique has certain inherent advantages over wire wrapping systems in which the bobbin is rotated. Thus for example, where a bobbin is rotated at high speed, centrifugal force tends to loosen the wire so that correct winding is rendered difficult or impossible. The device normally used for fly winding comprises a hollow shaft to which a cranked arm carrying wire guides is attached. A bobbin is placed inside the swing of the cranked arm and on the same axis as the shaft and wire is threaded through the shaft, around the wire guides of the cranked arm and is attached to the bobbin or to some point adjacent to it. Rotation of the shaft and the cranked arm while the bobbin is reciprocated axially wraps the wire around the bobbin and draws more wire over the guides and through the hollow shaft. This method involves a number of more or less sharp changes of direction for the wire which causes a drag effect similar to that produced when a rope is wrapped around a bollard for arresting the movement of a ship. This form of drag is called "bollard effect". The formula for "bollard" effect (the factor by which tension is multiplied as a result of directional change at a wire guide or bend in a guide tube) is e" where u is the coefficient of friction and 8 the change of direction in radians.

[0003] A typical cranked arm design will have four guides, one at each end of the hollow shaft and two on the cranked arm. The wire will make a 45° change of direction from the exit of the hollow shaft to the entry of the first guide, a further 45° change to bring it parallel to the rotational axis of the shaft and a final 90° change from the last wire guide onto the bobbin being wound, making a total of 180° of "bollard" effect. This however is only true in static or slow winding conditions.

[0004] When winding at high speed this is increased due to air resistance to the exposed length of wire being rotated and due to centripetal forces acting on the wire, causing it to take a non linear path between the guides. These effects are further increased when "flap" develops due to small imperfections at the wire supply reel and due to inherent speed changes of the wire when winding rectangular bobbins. This flap produces additional and flucuating "bollard effect" at the entry to the wire guides in the system. This fluctuating bollard effect is particularly disadvantageous because it may make it impossible to achieve a satisfactory average level of tension without producing peaks of tension in excess of the breaking strain of the wire. One variation of the cranked arm design that has been tried in order to overcome air resistance effects and centripetal effects uses an 'S' shaped tube. This stabilises the wire path but suffers from the fact that wear and friction occurs at the bends in the tube due to the difficulty of achieving a polished, wear resistant surface inside a bent tube. The separate guides of the conventional cranked arm design do not suffer from this disadvantage because they can be made of very hard ceramic material such as aluminium oxide in the form of a radiused eyelet that can be polished with diamond paste before assembly in to the flier. A cranked arm design with ceramic eyelets as described above but with tubes linking the ceramic guides would seem to overcome these problems but this suffers from difficulties of threading the wire when changing wire supplies. Also such a design retains the excessive 180° bollard feature mentioned above.

[0005] United States Patent Specification No. 4164331 described a flywinder which is conventional in the sense that bollard effect is high and in which friction in a sliding guide in the flier is reduced by the introduction of air under pressure or a lubricant.

[0006] To reduce bollard effect we have previously proposed in United States Patent Specification No. 4056238 a fly winder having a rotatable hollow conical flier and a rotationally stationary bobbin support concentric with the hollow conical flier, the flier and bobbin support being axially reciprocable towards and away from one another, wherein the hollow conical interior of the flier is a surface of rotation symmetrical about the axis of rotation of the flier forming a filament guide surface adapted to restrain outward radial movement of the filament, said surface of rotation increasing in diameter substantially smoothly along its length from an axially directed filament inlet guide closely circumscribing said axis at substantially the apex of said surface of rotation, the greater the diameter end of the hollow interior being disposed adjacent to the bobbin support and being of diameter such that a bobbin or like former mounted on the support can be received therein, filament guide means being disposed at or adjacent to the greater diameter end and through which the filament is to be constrained to pass before being wound on the bobbin or like former with the filament having freedom of circumferential movement intermediate the filament inlet and the filament guide means.

[0007] The conical hollow, interior of the flier is arranged so that the. wire enters the hollow interior substantially on the axis of rotation of the flier. In such an arrangement the wire on entering the flier is free to assume its own position in the wire guide, and it has been found in practice that the wire tends to assume a helical formation before passing through the final guide member, because in passing from the apex towards the rim of the cone, the rotational speed of the wire increases rapidiy. Due to inertia the wire lags behind the rotating surface until the tension of the wire balances the lag forces. It was thought that the helix of wire would act as a reservoir which would absorb the fluctuations in feed rate demanded when winding rectangular bobbins and damp out small tension increases which arise due to imperfections on the supply reel of wire.

[0008] We have However discovered that particularly with increased winding speeds the benefit due to formation of the reservoir is offset by the bollard effect still inherent in such an arrangement. We have identified one particular area for improvement as being the final wire guide since due to formation of the helix in the flier the wire changes direction through more than 90° at this point.

Disclosure of invention

[0009] Accordingly the present invention is a rotatable flier having a hollow interior which is a surface of rotation symmetrical about the axis of rotation of the flier and which is conical over at least a major portion of its length, said surface of rotation increasing in diameter smoothly along at least a major portion of its length from an axially directed filament inlet guide closely circumscribing said axis, the greater diameter end of the hollow interior being adapted for disposition adjacent to the bobbin support and being of diameter such that a bobbin or like former mounted on the support can be received therein, final filament guide means being disposed at or adjacent to the greater diameter end and through which the filament is constrained to pass before being wound on the bobbin or like former, and characterised by filament guide means disposed in the hollow conical interior of the flier intermediate the ends thereof to restrain the filament against circumferential movement relative to the interior surface of the flier during winding, the guide means comprising a plurality of eyelets or other discrete guides spaced along the hollow conical interior surface of the flier in a rectilinear array.

[0010] Advantageously the angle between the filament guide means and the axis of rotation of the flier is 14° plus or minus 1°.

[0011] The flier is itself preferably substantially conical in shape and is symmetrical about its axis of rotation to facilitate high speed operation by being of low mass and inherently good balance.

Brief description of drawings

[0012] In order to enable the invention to be more readily understood embodiments thereof will now be described by way of example with reference to the accompanying drawings, in which:

Figure 1 is a partly sectional view of an embodiment of an apparatus for fly winding an electrical coil;

Figure 2 is enlarged cross-sectional view of the flier;

Figure 3 is a cross-sectional side elevation of another embodiment of fly winding apparatus incorporating the invention;

Figure 4 is a cross-sectional rear view of the apparatus of Figure 3; and

Figure 5 is an enlarged cross-sectional side elevation of the apparatus of Figures 3 and 4.

Best mode of carrying out the invention

[0013] In Figures 1 and 2 of the drawings an apparatus for winding an electrical coil comprises a hollow flier 1, one end 2 of which is supported by a pair of ball bearings generally indicated as 3 so that the flier is rotatable about its axis. The bearings 3 are of conventional construction and so are not described in detail. The flier 1 is generally frusto- conical in shape and is formed at its said one end with a generally cylindrical section 4 to facilitate the mounting thereof in the bearings 3. Internally the flier is formed with a substantially conical recess 5 extending through the flier from end to end so that the flier is a hollow thin-walled tubular member. A ceramic guide member or eyelet 8 is mounted to define the entrance to the smaller diameter end 6 of the conical recess.

[0014] The filament guide means in the interior of the flier consists of a rectilinear array of ceramic eyelets 29 spaced along the conical recess 5 and terminated by a ceramic eyelet 9 at the free end of the flier.

[0015] The wire is constrained to pass through the array of eyelets before it is wound on a bobbin, and in so doing the wire is constrained to follow a substantially straight path through the flier. In this way the bollard effect when the filament leaves the end of the flier is reduced. The conical flier functions to support the filament guide means for rotation at high speed. The eyelets may be secured in position in the conical flier in any convenient manner and may for example be secured by means of wire ties and/or by means of an adhesive such as an epoxy resin.

[0016] A counter-balancing weight 30 is provided opposite the guide means or alternatively a pair of guide means may be disposed diametrically opposite one another. The bobbin 10 is mounted on the end of a support shaft 11 which is arranged to reciprocate such that the bobbin moves between a position in which it is disposed wholly within the flier (as shown) and a position in which only the free end of the bobbin is within the conical flier.

[0017] The means for rotating the flier and the means for reciprocating the shaft 11 will now be described.

[0018] A transmission shaft 15 supported in bearings 16 is arranged to be driven by an electric motor (not shown). A toothed wheel 12 is fixedly secured on the shaft 15 between the bearings 16 and transmits the drive of the shaft 15 to the flier by means of a toothed belt 13 (shown in dash-dot lines) and a toothed drum 14 fixedly mounted on the flier 2. The drum is of sufficient length to accommodate two drive belts if desired. At the end of the shaft 15 remote from the flywheel is a wheel 17 connected by a belt 18 to a wheel 19 on the input shaft of a gearbox 20. Conveniently a worm-reduction gear is employed, e.g. having a reduction ratio of 40:1. A cam device may be incorporated for changing the reduction ratio.

[0019] The output shaft of the gear box 20 drives a first toothed wheel 21, which meshes with a second toothed wheel 22, which in turn meshes with a third toothed wheel 23. The second and third toothed wheels 22 and 23 are associated with right-hand and left-hand clutches 24 and 25 respectively. The right-hand clutch is arranged to drive a pinion 26 and the left-hand clutch a pinion 27, both of which engage a rack 28 mounted on the shaft 11. It will be appreciated that when the right-hand clutch is engaged, the rack 28, and with it the shaft 11, are moved in one axial direction, and when the left-hand clutch is engaged the rack 28 and shaft 11 are moved in the opposite axial direction. In each case, the pinion 26 or 27 which is not engaged freewheels.

[0020] Limit switches (not shown) are provided for limiting the traverse of the rack 28 by transmitting a signal effective for disengaging one clutch and engaging the other. Disengagement and engagement are effected by means of a pneumatic system which is shown in Figure 1 beneath the clutches. This system will not be described in detail because it is of conventional nature.

[0021] It will be appreciated that in the aforedescribed apparatus the speed of rotation of the flier is proportional to the speed of reciprocation of the shaft 11. This is important in order that a uniform spacing is achieved between the turns of the coil being wound.

[0022] When very high speeds are required, the electric motor may be replaced by a turbine.

[0023] The embodiment of fly-winding apparatus of Figs. 3 to 5 is of the kind generally described above with the important difference that in the present case the fliers are axially reciprocatable and the bobbin supports are axially stationary.

[0024] The fly winding apparatus comprises a stationary box-like frame 41 in which a carriage 32 is mounted for reciprocation on a parallel pair of cylindrical rods 36 and 37 respectively which are stationarily mounted in the frame 41. The carriage is mounted for reciprocation without play on sets of linear bearings 38 which engage the rod 36 and the carriage carries a pair of rollers or followers 39 which engage opposite sides of the rod 7. In this manner the carriage can be reciprocated without play in the stationary frame. Reciprocation of the carriage is controlled by means of a hydraulic ram 40 the cylinder of which is fixed to the stationary frame and the rod of which is fixed to the carriage. Four vertically superposed conical fliers 1 of the kind generally described above are carried by the carriage and are mounted in bearings 3 so that they may be driven in rotation about their axes. In this way it is possible to support the fliers for rotation at very high speed and at the same time to reciprocate the fliers relative to stationary bobbins 10 so that wire may be wound on the stationary bobbins.

[0025] As is shown in Figures 4 and 5 of the drawings the stationary frame 41 carries a drive shaft 43 which is journalled in the frame for rotation about its axis but which is axially fixed. The drive shaft is formed with. splines 50 which are engaged by correspondingly splined pulleys 44 and 45 respectively which are mounted in the carriage 32 so that the pulleys are fixed for rotation with the shaft 43 but are axially slidable thereon during reciprocation of the carriage. Each of the fliers 1 is formed with a corresponding pulley 14 and toothed belts 13 and 13' respectively are engaged with the respective pulleys such that the pulley 44 drives a belt 13 which is engaged with the uppermost and the lowermost of the pulleys 14 while the pulley 45 drives a belt 13' which engages the two intermediate pulleys 14. The belts are preferably toothed belts. The drive shaft 43 is rotated by an electric motor (not shown in the drawings) which is connected to the drive shaft by means of a flexible belt and through a drive pulley 57 mounted on the drive shaft. The fliers are -thus driven in rotation at high speed during reciprocation of the carriage.

[0026] Wire guides 60 are mounted on the carriage 32 and are axially aligned with the fliers so that the wire to be wound on the bobbins may be guided from a reservoir through a stationary frame and to the inlet of the fliers 1.

[0027] Industrial applicability Although the invention has been described both generally and particularly with reference to winding wire for an electrical coil, the invention can be used for winding other coils, and for winding threadlike elements other than wire.

Claims

1. A rotatable flier having a hollow interior (5) which is a surface of rotation symmetrical about the axis of rotation of the flier (1) and which is conical over at least a major portion of its length, said surface of rotation increasing in diameter smoothly along at least a major portion of its length from an axially directed filament inlet guide (8) closely circumscribing said axis, the greater diameter end of the hollow interior being adapted for disposition adjacent to the bobbin support and being of diameter such that a bobbin or like former mounted on the support can be received therein, final filament guide means (9) being disposed at or adjacent to the greater diameter end and through which the filament is constrained to pass before being wound on the bobbin or like former, and characterised by filament guide means (29) disposed in the hollow conical interior (5) of the flier (1) intermediate the ends thereof to restrain the filament against circumferential movement relative to the interior surface of the flier during winding, the guide means (29) comprising a plurality of eyelets or other discrete guides spaced along the hollow conical interior surface (5) of the flier (1) in a rectilinear array.

2. A rotatable flier according to any preceding claim, wherein the angle between the filament guide means (29) and the axis of rotation of the flier is 14°±1°.

Ansprüche

1. Drehbarer Flügel mit hohlem Innenraum (5) mit einem Umlaufquerschnitt, der mit der Drehachse des Flügles (1) symmetrisch und über wenigstens den größten Teil seiner Länge kegelig verläuft, bei dem sich der Durchmesser des Umlaufquerschnittes über wenigstens einen größeren Teil seiner Länge einheitlich von einer axial verlaufenden, die besagte Achse eng umschließenden Fadeneinlaufführung (8) ab vergrößert und bei dem das Ende des hohlen Innenraumes mit dem größeren Durchmesser für eine Anordnung neben der Spulenhalterung ausgebildet ist und einen solchen Durchmesser aufweist, daß eine Spule oder ein ähnlicher auf der Halterung montierter Körper in diesen Durchmesser hineinpaßt, wobei Fadenendführungsmittel (9) an oder neben dem Ende mit dem größeren Durchmesser angeordnet sind, die der Faden durchlaufen muß, ehe er auf die Spule oder einen ähnlichen Körper aufgewickelt wird, gekennzeichnet durch im kegelig verlaufenden Hohlraum (5) des Flügels (1) zwischen dessen Enden angeordnetes Fadenführungsmittel (29) zur Verhinderung von Bewegungen des Fadens in Umfangsrichtung relativ zur Innenfläche des Flügels beim Spulen, wobei besagtes Führungsmittel (29) eine Vielzahl von Ösen oder anderen, getrennten Führungen aufweist, der auf der kegelig verlaufenden Innenfläche des Hohlraumes (5) des Flügels (1) geradlinig verlaufend angeordnet sind.

2. Drehbarer Flügel gemäß 1, bei dem der Winkel zwischen Fadenführungsmittel (29) und Flügeldrehachse 14°±1° beträgt.

Revendications

1. Une ailette de renvidage rotative ayant un intérieur creux (5) qui est une surface de rotation symétrique par rapport à l'axe de rotation de l'ailette (1) et conique sur au moins la plus grande partie de sa longueur, ladite surface de rotation augmentant progressivement de diamètre sur au moins une partie majeure de sa longueur à partir du guide d'entrée de filament (8) à direction axiale circonscivant de près ledit axe, l'extrémité de plus grand diamètre de l'intérieur creux étant adaptée pour être placée à côté du support de bobine et ayant un diamètre tel que le support peut recevoir une bobine ou dispositif de mise en forme, les moyens de guidage final du filament (9) étant disposés à ou adjacents à l'extrémité de plus grand diamètre et à travers desquels le filament est constraint de passer avant d'être enroulé sur la bobine ou tout dispositif de mise en forme similaire et caracterisé par un moyen de guidage de filament (29) placé à l'intérieur creux conique (5) de l'ailette (1) situé entre les extrémités de cette dernière pour empêcher tout mouvement circonferenciel du filament par rapport à la surface interne de l'ailette pendant l'enroulage, le moyen de guidage (29) étant constitué d'une pluralité d'oeillets ou d'autres guides discrets espacés le long de la surface intérieure creuse conique (5) de l'ailette (1) selon une série rectiligne.

2. Une ailette de renvidage rotative conforme à la revendication précédente dans laquelle l'angle entre le moyen de guidage du filament (29) et l'axe de rotation de l'ailette est de 14°±1°.

Drawing