FR2510088A1 - VOLTAGE CONTROL APPARATUS AND WIRE COMPENSATION - Google Patents

Abstract

APPARATUS IN WHICH A THIN WIRE IS UNWINDED AT HIGH SPEED THROUGH A TENSIONER ASSEMBLY 44 INCLUDING TWO FRICTION PADS 46 BETWEEN WHICH THE WIRE PASSES; THE LOCKING PRESSURE EXERCISED ON THE FRICTION PADS 46 IS CONTROLLED BY ADJUSTABLE LOCKING PARTS 48, 52, 66; THE WIRE THEN PASSES AROUND A PULLEY 70 AND THROUGH A MOU COMPENSATION ASSEMBLY 94 INCLUDING TWO FIXED EYELETS 100, 102 SPACES FROM ONE THE OTHER AND ONE EYELET 104 PLACED AT THE END OF AN ARM LIGHT WEIGHT OSCILLATING 106 WHICH IS ARRANGED BETWEEN THE FIXED EYELETS TO ABSORB THE SOFT IN THE WIRE; AN ADJUSTABLE COUNTERWEIGHT 124 IS PLACED ON THE SWING ARM TO ENSURE THAT IT SPREADS THE WIRE OF A STRAIGHT LINE PATH CONNECTING THE TWO FIXED EYELETS; FURTHERMORE, A WIRE BREAK IS DETECTED BY A PULLEY 70 ROTATION CONTROL ELEMENT. APPLICATION TO ARMUTE AND STATOR WINDING MACHINES.

Description

The present invention relates to a tension and compensation apparatus

  of wire arranged notaiment to be used in

  armature winding machines where fine wires are wound

  The invention can also be used with other winding machines; in particular stator winding machines and, in general, in all cases where a wire is unwound in response to unequal needs at high speeds. Several types of unwinding or unwinding devices have been proposed and used. These devices are generally mounted in a position closely adjacent to a spool of thread, and they are arranged in such a way as to exert a certain tension on the thread. They are also typically provided with means of equalizing the voltage according to the needs of the machine using the wire The unwinding devices

  or reeling available can be used satisfactorily

  However, no fully satisfactory unwinding device is available for use in the very high speed winding of windings formed of a fine wire, in cooperation with armature winding machines, because of the speed at which the device must react to accommodate varying wire requirements during winding of a winding and while collector connections are being established between windings. Unwinding devices are particularly difficult to solve in the case of armature winding from a fine wire which breaks easily under the effect of the unequal tension applied to it and which can cause the wire to be twisted or entangled, or simply placed Ln

  under a voltage greater than that to which he can resist.

  The problems associated with winding such armatures are

  Because of the particular requirement to wind a large number of turns for each coil. For example, it is common to make coils having a number of turns greater than 1500 using a very fine wire, for example a wire of 0.08. diameter of this type of armature can be wound on winding machines of the double rocker type, where the rockers rotate at speeds above 3000 rpm. Considering that the wire is guided in armature notches by an armature. tooling that necessarily creates different yarn requirements when each turn of the reel is wound, there are usually two maximum need intervals in yarn and two minimum or no need intervals in yarn per turn, and the uncoiler must be able to respond differences in wire requirements at a frequency greater than 10 000 maximum per minute during the winding of a winding The unwinding device must also be capable of responding to relatively large variations in wire requirements during the intervals between windings windings in which the connections

between conductors are formed.

  In accordance with the present invention, there is provided an

  similar tension and compensption of wire usable as a

  unwinder and able to implement a very fine wire

  The apparatus according to the invention is inexpensive to manufacture, has a simple and robust operation and comprises a relatively simple wire tension assembly which has two friction pads that are mounted

  so that the thread passes between them and that the skates

  friction by the movement of the wire The pads have a relatively large surface so that the wire enters

  contact with it over a fairly long length.

  Locking means are provided for urging the pads towards each other, said locking means being adjustable so that frictional forces acting on the wire can be adjusted. After initial setting of the blocking pressure for an operation particular winding, it is not normally necessary to make any other adjustment to the blocking pressure. The friction pads create the only significant tension exerted on the wire, so that the

  resistance opposed by friction to the movement of the wire is es-

sensibly uniform.

  The apparatus according to the invention further comprises a wire assembly comprising a light weight swing arm which is pivotally mounted at a point adjacent to an extremity which has at its other end an eyelet through which the wire passes. thrust is exerted on the swingarm so as to pull the wire during intervals when there is a demand for slack resulting from the movement of the armature or other device that pulls the wire.

  can be exerted by a weight mounted on the swingarm.

  This weight can be all that is needed to be used

  with a very fine wire, for example a wire of 0.06 mm in diameter.

  A spring connected to the weight is used to increase the thrust to be involved during the unwinding of a thread

of a larger diameter.

  The path of the thread in the tensioning assembly is vertical while the path of the thread in the compensation assembly is preferably horizontal, the change of direction being ensured by a pulley. In addition, according to the present invention, there is provided a detector to control the rotation of the wire pulley so that, in case of breakage of the wire, stop the rotation of the pulley is detected This event can be used to trigger an alarm, or to stop

  the operation of the machine with which the apparatus according to

vention is used.

  The object of the invention is to provide a tension apparatus

  wire compensation which is simple, robust and inexpensive

  as described above and, also, to provide a

  reil of this kind that can occupy the minimum of space -

  All the mechanical parts of the invention can be mounted on a single plate that does not need to have dimensions greater than 200 x 200 mm The sensor used to control the rotation of the pulley and therefore the breaking of the wire, as described above, can be mounted on

the same plate.

  Furthermore, in accordance with the present invention, there is provided a very simple means for maintaining the control of the wire in order to retain it on the pulley. This problem is solved by the simple expedient of mounting a brush provided with bristles on the pulley so that it prevents the wire from going out

throat of the pulley.

  Other advantages and features of the invention are

  will be highlighted, in the following description, given

  by way of non-limiting example, with reference to the drawings

annexed in which: -

  Fig 1 is a front elevational view, with parts

  shown in broken view, of the tension and yarn compensation apparatus according to the invention, shown in association with a rocker arm of an armature winding machine, the figure also showing the drive and control circuit. Figure 1 also shows a portion of a wire guide cone used to hold the wire in its path from a feed reel, and a portion of a shaft for mounting the wire. apparatus according to the invention on the bench of the armature winding machine; Fig 2 is a side elevational view of a portion of the apparatus of Fig 1, corresponding to arrows 2-2, this figure showing in particular a wire tension assembly; Fig. 3 is a sectional view of a portion of the apparatus of Fig. 1 taken on line 3-3 and showing in particular a swingarm pivot assembly; Fig 4 is a plan view of a part of the apparatus

  of FIG. 1, made in correspondence with arrows 4-4 and FIG.

  in particular a wire pulley, the apparatus preventing the wire from coming out of the groove of the pulley, as well as a detector

  to control the rotation of the pulley; Fig 4 also shows

  schematically a wire breakage detection circuit which is electrically connected to the detector; Fig 5 schematically shows the wire pulley and the detector, according to a view made from the rear face of the pulley; Fig. 6 is a perspective view, partly broken away, and with parts shown broken away from the apparatus and the associated machine part shown in Fig. 1,

  the figure further showing a wire feed reel.

  In Figs. 1 and 6, the apparatus according to the invention has been designated as a whole by 10 and, as shown in the drawings, it is used to guide an insulated wire from a supply coil 12, housed in a container 14 open at its ends, to the hollow spindle 16 of a set to

pendulums, designated by 18.

  As the experts of armature winding machines know, the wire moves from a balance pulley 20 placed at the free end of a rocker arm 22

  armature core (not shown) to be wound.

  The yarn tension control apparatus according to the invention may comprise a single bearing plate 24 which is mounted on a shaft 26 fixed to the bench (not shown) of the winding machine, and is held in a desired position by a set screw 28 engaged in a fixed mounting block 30

  on the back of the bearing plate 24 by screws 32.

  The thread unwound from the spool is prevented from ballooning excessively

  by means of a cane 34 and it enters a training tube 36 extending vertically and mounted in a bracket 38, fixed on the lower front face of the bearing plate 24 by screws 40 The cone 34 can be supported on the bracket 38 by A carrier assembly 42 The dressing tube 36 functions as a wire guide entering the tensioning and compensating apparatus according to the invention. As can be understood by those skilled in the art, the wire dressing tube 36 is preferably provided, at least at its lower end,

  of a tungsten carbide grommet because the thread penetrates

  trant by the lower end of the dressing tube 36 thus moves in a spiral and could produce abrasion

  considerable at the lower end of the dressing tube 36.

  The wire coming out of the upper end of the dres-

  wise 36 passes through a set of thread tension, designated 44 and comprising, as shown in Figs 2 and 6, two circular friction pads 46 which are placed opposite one another and which are mounted between two circular blocking members comprising a cup-shaped base member 48 and a drum-shaped housing member 50 provided with an enlarged pan-shaped end portion 52 which is placed facing the base 48, such that the base 48 and the large end 52 of the casing 50 cooperate to closely hold the friction pads 46 to one another. The casing 50 further comprises a small end portion 54 which is provided with a cylindrical boss 56 projecting towards the end. The friction pads 46, the base 48 and the housing 50 all have aligned apertures which are coaxial with the helical spring 58 so as to be received. an elongated mounting threaded stud 60 which passes therethrough and which projects perpendicularly from the end face of the bearing plate 24. One end of the stud 60 is engaged in an opening 62 which passes through the bearing plate 24, receiving a nut 64 on the The opposite end of the stud 60 is threaded to receive two adjusting knurling nuts 66 and 68. Thus, the adjusting nut 66 can be rotated to increase the compression of the spring 58 and thereby to so that the housing 50 exerts a higher blocking pressure on the friction pads 46 to thereby increase the frictionally opposed resistance to the movement of the wire W

passing between them.

  Friction pads may consist of different

  materials to create friction

  resistance to the movement of the wire without ex-

  stantially on the insulating coating on the wire.

  Different materials can be used for different types of yarns. For very fine yarns with a diameter of approximately 0.12 to 0.06 mm, it is preferred to use a dense felted material. Skates 46 made of dense felt can be locked in place. -contact each other, with the wire passing between them Because the wire is elastic,

  felt pads have a good resistance to wear.

  It should be noted that the structure of the casing 50 facilitates an operator the task of manually pulling the casing 50 to move it away from the bearing plate 24 in opposition to the force of the spring 58 in order to separate the pads 46 when this operation is carried out for example, when a spool of spent wire is replaced by a full spool, it is also possible, because of the mounting mode of the elements of the tension assembly on the stud 60, to rotate the housing 50 and, with this, the adjacent pad 46, so as to change the relative position of the outer pad relative to the path of the wire and therefore minimize the wear on the pad It is obvious that both pads can be manually turned when the

  housing 50 is spread by pulling the bearing plate 24.

  It has been found that a relatively large length of the pad 46 must be in contact with the wire. If the contact is established with a length that is too short, the wire may, in

  the area between the supply reel 12 and the

  seems to tension 44, be excessively twisted and it can knot, tangle and break For this reason, the axis of the stud 60 is placed in a position as close as possible

  the vertical path of the wire without hindering the movement of the latter.

  For winding performed with a fine wire, it has also been found that circular pads 46, formed of a dense felt and having a diameter of about 54 mm, so that the wire is in contact with the pads over a length of 'about

  mm, gave satisfaction We would not get any results

  satisfying states with pads of a much larger diameter

small, for example 25.4 mm.

  At the exit of the wire tension assembly 44, the wire W is guided along a path passing around a pulley 70 mounted by means of a roller bearing 72 on an axis 74. 74 may advantageously be in the form of a screw having a large head abutting against the inner ring of the bearing 72 and provided with a threaded end engaged in a hole 76 household in the bearing plate

  24 and receiving a locking nut 78 The pulley 70 is now

  naked spaced from the front face of the bearing plate 24 by a

spacer 80 surrounding the axis 74.

  The pulley 70 is mounted on the bearing plate 24 of

  way that its wire receiving groove 82 is vertically aligned

  wedge with the vertical axis of the wire adjustment tube 36 so

251008-8

  to define the vertical path of the wire W, and horizontally with the axis of a balance pin pulley 21 Because the wire changes direction on the pulley 70, it tends, depending on the high speed of operation of the armature winding machine, to jump from the groove 82 of the pulley. To prevent this from occurring, a wire retainer in the form of a brush 84 provided with bristles 86 is mounted with a screw 88 so as to pass through an opening in the brush 84. and in an aligned threaded hole 88 formed in the bearing plate 24, the pin 84 being kept spaced from the front face of the bearing plate 24 by a spacer 92 The bristles 86 are placed in the assembly above the pulley 70 1 along the horizontal path of the wire coming out of it Preferably, the bristles are close or even in slight contact with the wire to prevent it from coming out of

the groove 82 of the pulley.

  As indicated above, the thread tension assembly 44 creates a substantially uniform tension in the yarn W so as to produce the necessary strength to

  correct operation of the pendulum assembly 18.

  During intervals where the yarn requirement created by rotation of the beam 18 is minimized or ceased, the relative slack condition in the yarn is suppressed or absorbed by a compensator assembly designated 94 and including two yarn guides 96, 98 spaced apart from one another and provided with eyelets

  and 102 which are aligned coaxially with the horizontal path

  zontal of the wire extending from the pulley 70 to the pulley 21.

  The wire guiding assemblies 96 and 98 may comprise welded elements provided with studs or similar members (not shown), extending into holes in the

  bearing plate 24 and mounted thereon in an appropriate manner.

  The part of the wire W that extends between the guide grommets

  and 102 passes through an eyelet 104 placed at the end

  mity of a swing arm 106 pivotally mounted on the front face of the bearing plate 24 via an assembly 108, better visible in Figure 3 and comprising an axis 100 rotatably mounted in a needle bearing 112 maintained The shaft 110 has an enlarged head 114 provided with a hole 116 oriented transversely and intended to receive the oscillating arm 106. The front face of the enlarged head 114 comprises a threaded hole receiving a screw. setting 118 used to lock the swing arm 106 on the pivot assembly 108 A retainer ring 120, provided with a locking screw 122 for retaining it on the central axis 110 is mounted on the axis in an adjacent position on the face

  rear of the bearing plate 24 With correct lubrication

  recte, the pivot assembly 108 allows free rotation

swing arm 106.

  To obtain the best possible performance, the oscillating arm 106 is preferably made with a weight as light as possible so that it can move rapidly to the position shown in Figs 1 and 6, where its eyelet 104 is aligned with the fixed guide eyelets 100 and 102 in response to traction exerted on the wire by

  the pendulum assembly 18 was made an oscillating arm appli-

  Owned from a 0.85 mm diameter piano wire with a small tungsten carbide eyelet diameter

inside 4 mm.

  The light weight structure of the swing arm 106 and the pivot assembly 108 allows the swing arm 106 to respond quickly to an increase in tension in the wire passing between the guide eyelets 100 and 102.

  oscillation arm 106 to rapidly compensate for

  slack in the wire by a downward movement of the eye 104 of the oscillating arm from the horizontal path of the wire, the oscillating arm 106 is urged to turn clockwise, looking at the FIG. 1, by a thrust means comprising a weight 124 which may be in the form of a short section of a cylindrical metal rod provided with a transversely oriented hole and in which the oscillating arm 106 is engaged, the weight comprising at one end a tapped hole which is intended to receive a locking screw 126 for its attachment to the swing arm 106 The weight 124 further comprises a hole for receiving

  one end of a helicoidal spring 128 whose other end

  mité is engaged in a hole 130 of an arm 132 which is mounted on the bearing plate 24 by one of the aforementioned screws 32 and which is spaced from the front face of the bearing plate 24 by a spacer 134 The arm 132 is provided a plurality of spaced apart holes allowing additional adjustment of the spring tension applied to the swing arm 106. Another adjustment may be made by loosening the locking screw 126 and moving the weight 124 thereagainst in some applications. especially when using a very fine wire such as a wire of 0, 06 mm in diameter, the coil spring 28 may be useless, the weight 124 being sufficient to provide the desired compensation As will be understood by those skilled in the art. the material, the oscillating arm 106 rotates in a clockwise direction, looking at Fig 1, to possibly remove the slack created during the rotation intervals of the balance and, also when the The pendulum stops or rotates in the opposite direction when making the connection between conductors. The maximum stroke of the oscillating arm 106 in the direction of clockwise can be limited by a stop 136 which can comprise an introduced pin.

  in a hole in the bearing plate-24

  It follows that the compensation assembly designated by 94 exerts an adjustable thrust within wide limits and intended to be applied to the oscillating arm 106 which is advantageously provided with an eyelet 104 to compensate for the slack. The use of a grommet 104 is considered as necessary, because of the very high speeds at which the armature winding machine can operate, to make sure that the wire is not

separated from the swingarm.

  In addition, in accordance with the present invention, the wire feed pulley 70 can be used in a wire feed system.

  wire break detection, which can be used to trigger

  expensive an alarm and / or to stop the winding machine.

  With reference to FIGS. 5 and 6, the pulley 70 can be made

  nylon or other suitable plastic material and not

  conductor, which is provided with a metal foil or the like 138 covering a circular segment of its rear face A proximity detector or other suitable probe 140, is mounted on the carrier plate 24 by means of a fixing plate 42 held on the rear face of the bearing plate 24 by the pulley axis 70 and its mounting nut 78, as well as by a screw 144 screwed into a hole 146 threaded in the bearing plate 24 Preferably, the plate bearing 24 has a notch in which the detection probe 140 is engaged partially so as to be able to

  apply tightly against the rear face of pulley 70.

  Signals provided by probe 140 may be applied to a suitable wire-break detection circuit and schematically shown at 150 to control the rotation of the pulley, said signals being used by detector 150 to determine if pulley 70 is still in rotation; in the event that it stops rotating during an interval where it should rotate, which may be caused by a wire break, an appropriate alarm may be triggered, or the detector 150 may include a circuit of known type which produces a break in operation of a conventional control and balance drive circuit, shown schematically at 152 in Fig 1 and used to control the operation of the rocker assembly 18 to ensure that the pulley 70 rotates constantly while the wire W is being unwound from the feed reel 12, it may be necessary to form a complete loop of wire W around the pulley 70. In other cases, it is sufficient to

  simply pass the wire on the pulley 70.

  An appropriate supporting plate 24, according to the invention,

  does not need to have dimensions greater than 200 x 200 mm.

  All wire guide portions which are mounted on the carrier plate 24 are preferably spaced therefrom by a distance such that the longitudinal axes of the entire wire strand extending from the lower end from the dressing tube 36 to the balance pin pulley 21 is located in a common vertical plane to minimize the forces acting on the wire as it travels through the apparatus according to

the invention -

  As mentioned before, the eyelet provided at the end

  lower half of the dressing tube 36 and the swing arm eyelet 104 are preferably formed of tungsten carbide,

  because of its good resistance to abrasion The same consideration

  ration applies to the thread passing eyelets 100 and 102 and

at the eye 104 of the swingarm.

Claims (10)

  A tensioning and compensating apparatus usable with a wire being unwound from a high speed feed reel, characterized in that it comprises: incoming wire guiding means (36) placed in a position adjacent said coil and wherein the wire therefrom passes; a compensator assembly (94) comprising two spaced-apart guide means (100, 102) contacting the wire and defining a path along which the wire passes, an oscillating arm (106) having a eyelet (104) through which the section of wire extending between said guide means and path definition,   and pushing means (124) for pushing the oscillating arm   removing the last-mentioned thread section out of the path defined by the guide means (100, 102) when necessary to compensate for a slack; and a wire tension assembly (44) comprising a friction means (46) contacting the wire between the input guiding means (36) and the compensator assembly and further comprising a locking means (50). ) adjustable to exert on said friction means (46) a pressure for frictionally creating an adjustable resistance   movement of the thread through said set of tension.   2 Apparatus according to claim 1, characterized in that said friction means (46) comprises a set of skids   arranged to be applied against the wire for a certain length of time   of it to virtually prevent unwound wire   the coil to twist or get tangled.   Apparatus according to claim 2, characterized in that said set of pads is formed of a dense felted material.   4. Apparatus according to one of claims 2 or 3,   characterized in that said set of pads comprises two friction pads.   5. Apparatus according to claim 4, characterized in that the friction pads (46) have aligned holes for receiving a stud (60) projecting from a bearing plate (24), said adjustable locking means (60). comprising a locking member pressing against one of the pads and slidably mounted on said stud (60), a helicoidal spring (58) surrounding said stud and pressing against the locking member (60), and a nut adjustment (66) screwed onto the stud and urging the spring to ensure his compression.   Apparatus according to any of the claims   1 to 5, characterized in that said thrust means (124)   includes a sliding weight along the os arm   (106) and means (126) for releasably locking said weight on the swingarm.   Apparatus according to claim 6, characterized in that said biasing means further comprises a spring (128) connected to said weight.   Apparatus according to any of the claims   1 to 7, characterized in that a direction change means (70) aligned with said input guide means (36) is provided to cause the thread to move in a substantially vertical path between said means guide means (36) and said direction change means (70), and in that said guide means (100, 102) cooperate with said direction change means (70) to cause the thread moves in a substantially horizontal path   when passing in front of said means of change of direction.   Apparatus according to claim 8, characterized in that said change of direction means (70) comprises a   pulley around at least a portion of which passes the wire.   Apparatus according to claim 9, characterized in that there is provided means (140) for controlling the rotation of   said pulley to detect a wire break.