US3811629A

US3811629A - Process of winding cores

Info

Publication number: US3811629A
Application number: US00300456A
Authority: US
Inventors: R Sedgewick
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-12-21
Filing date: 1972-10-25
Publication date: 1974-05-21
Anticipated expiration: 1991-05-21

Abstract

In toroidal core winding apparatus, wherein the wire to be wound is stored as a helix within a hollow hoop and the hoop as it rotates through the core dispenses the wire from a point on the edge of its inner periphery; the hoop consists of a flexible hollow steel or plastic tube that can be maintained in the shape of a distorted circle; e.g., an elongated oval or racetrack shape, by guide wheels so that the hoop, for at least an appreciable portion of length on its periphery, moves in a straight line as it passes through the core, thus permitting the diameter of the tubing forming the hoop to be larger. Significant advantages of this invention are that: (a) the straight run permits the wire to be drawn down tight on the core largely along its line of travel; and (b) the wire can be wound on the core in either direction by simply reversing the direction of rotation of the hoop. Also, two strands of wire can be payed out simultaneously from the hoop. This can be done in any conventional manner. For example, motor 20 can be a reversible motor.

Description

United States Patent [191 Sedgewick [111 3,811,629 [451 May 21, 1974 Related US. Application Data [63] Continuation-impart of Ser. No. I00,277, Dec. 21,

1970, abandoned.

[52] US. Cl. 242/4 A, 242/7.03 [51] Int. Cl. H0lf 41/08 [58] Field of Search 242/4 A, 4 R, 4 BE, 7.14,

[56] References Cited UNITED STATES PATENTS 2,l85,883 l/l940 Berger 242/4 BE 2,978,l93 4/1961 Kelly 242/4 A 2,986,350 5/1961 Bugg 242/4 BE 2,102,692 12/1937 Franz 242/4 R Primary Examiner-Billy S. Taylor Attorney, Agent, or Firm-Lee A. Strimbeck 57] ABSTRACT In toroidal core winding apparatus, wherein the wire to be wound is stored as a helix within a hollow hoop and the hoop as it rotates through the core dispenses the wire from a point on the edge of its inner periphery; the hoop consists of a flexible hollow steel or plastic tube that can be maintained in the shape of a distorted circle; e.g., an elongated oval or racetrack shape, by guide wheels so that the hoop, for at least an appreciable portion of length on its periphery, moves in a straight line as it passes through the core, thus permitting the diameter of the tubing forming the hoop to be larger.

Significant advantages of this invention are that: (a) the straight run permits the wire to be drawn down tight on the core largely along its line of travel; and (b) the wire can be wound on the core in either direction by simply reversing the direction of rotation of the hoop. Also, two strands of wire can be payed out simultaneously from the hoop. This can be done in any conventional manner. For example, motor 20 can be a reversible motor.

I PATENTEUIAY 21 I974 INVENTOR RiCHARD D. SEDGEWICK ATTORNEY PROCESS or WINDING CORES RELATED APPLICATION This application is a continuation, in part, of Core Winding Device, U.S. Ser. No. 100,277, filed Dec. 21, 1970, and now abandoned by the present inventor.

PREAMBLE It is customary to wind hollow cores such as toroidal coils and motor strators by rotating a circular shuttle through the core. The shuttle has the winding wire stored thereon by circumferentially winding it around its pheriphery. The shuttle is split to permit insertion and removal of the core. However, the core must be first inserted into the shuttle and then the wire wound about the periphery of the shuttle, which is an awkward manner of operating and permits only wire sufficient for one core to be placed on the shuttle. Also, the wire must be payed out of the rim of the shuttle not in line with the central plane of rotation off the shuttle, which does not lend' itself to the winding of toothed cores, such as stators.

PRIOR ART Some prior art devices proposed a modified core winding device using a hollow tube in the shape of a closed circle. The wire to be wound is stored inside of the hollow tube in the form of a helix and payed out from a point on the inner peripheral edge of the hoop. Since the hoop is circular, a point on its edge describes a circular path as it travels through the core which proscribes the cylindrical length of the core and/or the tube diameter of the hoop.

US. Pat. No. 3,466,518, Rotary Stepping Motors and Control Systems Therefor, by V. Aylikci et a1. describes a motor construction that is of particular interest in that it has a toothed stator which is very difficult to wind because the bore is relatively small and the spacings or gaps between the stator poles are quite fine, calling for precise guidance of the winding wire as it is being passed through the gaps. Also, as shown in FIG. 1 of the patent, the cylindrical length of the stator can be quite long relative to the diameter of the bore.

THIS INVENTION This invention is an improvement of and contains the same essential elements as the prior art; i.e., a hollow hoop holding in the inside of the hollow tube a supply of the winding wire as a helix and adapted to dispense the same as a strand from a point on its inner periphery; guide means; e.g., idler and drive wheels, adapted to rotate the hoop through a hollow core, means for positioning the core to be wound and means for'releasably tensioning the wire during each revolution of the hoop.

The improvement of this invention comprises constructing the hoop of a tube of a flexible metal or plastic that can be constrained during operation by the guide means in the form of a distorted circle; e.g., an elongated oval or racetrack shape or D-shape. In this manner, the tube can be made to move as a straight line as it passes through the core which, with elongated cores; e.g., cores with an unusually high length to bore ratio, permits the cross-sectional diameter of the tube to be larger and/or thicker walled. Thus, the tube can have a greater storage capacity and/or can be stronger.

The hoop of this invention is made by bringing the ends of a resilient flexible tube; e.g., one of a steel, PVC, polypropylene, nylon, polytetrafluoroethylene and preferably an extruded polyethylene, together. The properties of the tube are such as to form a flexible or destortable circle when otherwise unrestrained, except by having the ends of the tube brought together. The wire is first placed in the tube as by winding it on a rodshaped mandrel, having a diameter smaller by at least two thicknesses of the wire than the inside of the hollow tube. The wire wound rod and the hollow tube are then lined up in a straight line end-to-end and the helix of wire is pushed off the rod into the tube, after which the ends of the tube can be brought together and held together as with a plug to form a circle.

To mount the wire-filled tube, it is snapped into the guide means which impose on it the race track shape, the ends of the tube are spread and the core is inserted therebetween, after which the ends are brought together and the core winding operation can commence.

THE DRAWING The drawing is a schematic side view in evaluation of the improved apparatus of this invention.

DESCRIPTION Referring to the drawing, the apparatus comprises a hollow tube 10 restrained in a racetrack form by means of idler wheels 11 and drive wheels 12, which are suitably grooved at their peripheries to accommodate the diameter of the tube. Tube 10 contains inside the fine wire in the form of a helix and a strand 13 of the wire is payed out at a point 14 on the inner periphery of the tube, as through a plug 10a tapped with a fine inwardly directing hole and adapted to maintain some tension on wire 13. Plug 10a press fits into both ends of the tube and keeps them aligned and together.

The stator 15 to be wound is suitably rigidly mounted by means not shown as by a clamp. If the ends of the tube are firmly held together, as by plug 10a being threaded therein, the tube can be maintained in the desired racetrack shape by two internal wheels in the same manner as a band saw, provided the wheels are split in the middle along the plane of rotation to permit passage of wire 13.

As illustrated, tube 10 is driven around the track provided by the guide wheels by means of a motor 20 driving drive wheel 12 through a belt drive 21, with the adjacent wheels being driven therefrom via

belts

22 and 23.

As is known, wire 13, during each revolution of hoop 10, is engaged by a tension means 16 which holds the wire relatively firmly until it is pulled taut against the stator 15, at which time the wire 13 slips through means 16. Means 16 can comprise two facing flat clutch-like pads, spring loaded to provide the necessary restraint. The pads are large enough and exert sufficient restraint so that the leading end of the wire is taut as it enters the stator.

Of course, it is not required that the sides of the moving tube be caused to move in a straight line except as it passes through the core. For example, the side opposite the core can be caused to move or be flexed inwardly in a curve to increase the effect length of the tube within the boundaries of the support frame, and/or also to increase the tension on the wheels engaging the tube. In this connection, guide wheels can be also placed on the inner periphery of the distorted circular shape as desired. Alternatively, the hoop can be maintained in a rounded D shape. In some cases, guide tubes or funnels instead of wheels can be used to position or direct the hoop.

In addition to the ease of operation and the increase in the number of windings for each time a new amount of wire must be stored, the apparatus of this invention has the significant advantage that when properly designed, the straight line run through the core permits the pull on the loop of wire placed on the core to be largely along the straight line of travel of the tube; i.e., along the longitudinal axis of the core, and not at any significant angle thereto. Thus, as the loop of wire is drawn tight, it is required to pass over a lesser number of sharp comers of the core. The wire can then be drawn tighter with less resistance and opportunity for chafing, and this permits more turns to be placed on a toothed stator having a limited slot area.

Two helixes of the core-winding wire can be stored inside of the hollow tube, one in one end, and one in the other end, and can then be payed out simultaneously from the hoop as it rotates in the guide means.

The use of flexible tube of this invention allows the apparatus to wind in either direction; i.e., it can reverse wind, without any change in the set-up. This can be done in any conventional manner. For example, motor 20 can be a reversible motor. A conventional shuttle cannot do this as the wire is wound around the circumference in one direction only. This reverse winding feature permits the establishment of desired magnetic polarities between interconnected windings without the need to solder or connect leads from each winding; i.e., the number of connections required between winding leads can be significantly reduced by reverse winding. For example, with reference to FIG. 5(b) of the Alylikci patent, showing one way of connecting windings in a toothed stator, at least one-half or 12 lead ends can be eliminated by reverse winding in accordance with the present invention.

EXAMPLE The core wound was a 12 toothed laminated stack stator. It had a height of 2% inches, and CD. of 2 inches, and a bore of inches. The stator had 12 teeth approximately 3/32 inches wide each, which left 12 gaps about 1/32 inches wide each through which the wire entered.

The hoop consisted of an extruded polyethylene tube of 2% inches O.D., inches [.D. and feet long. Eight guide wheels are used, three of which were drive wheels and each of which had a diameter at the groove line of 6 inches. The guide wheels maintained the tube in a racetrack shape and were equally spaced thereabout. The radius of curvature of the ends of the racetrack was 12 inches. The total travel per revolution of the tube was 10 feet. The tube was rotated at a rate of revolutions per minute.

The wire wound was No. 30, 100 turns per slotted section of the stator being required. Over 300 feet of this wire could be stored as a helix in the polyethylene tube at one time.

I claim:

1. A process of winding a filament toroidly onto a hollow cylindrical core, comprising, in combination, the steps of: i

a. providing a flexible hollow tube which, when the ends thereof are brought together, is rigid enough to form a circular hoop if the tube is otherwise unrestrained but which is flexible enough to accept distortion of said hoop into an elongated noncircular shape;

b. loading said tube with a filament in the form of a helix running along the length of said tube;

c. inserting said tube through a hollow cylindrical core and bringing the ends of said tube together;

d. mounting for rotation and constraining said tube into an elongated non-circular shape with a straight run connected by curved ends, by means of guides mounted on a frame, at least one of which guides is a rotating drive-guide;

e. guiding an end of said filament through a point on the inner periphery of said elongated non-circular shape and restraining said end;

f. positioning and mounting said hollow cylindrical core to said frame so that said straight run passes therethrough; and

g. rotating said drive-guide and thereby rotating and feeding said tube through said hollow cylindrical core and winding said filament toroidly thereon as the same pays out from said point on the inner periphery.

2. The process of claim 1 comprising in addition:

1. during step (b), placing a second helix of said filament in said tube:

2. at step (e), guiding an end of the filament of said helix through a second point on said inner periphcry; and

3. during step (g), simultaneously winding the filament from said helix onto said hollow cylindrical core.

3. The process of claim 1 comprising the additional step of:

h. during at least part of the winding cycle, reversing the direction of rotation of said tube and winding said filament toroidly onto said hollow cylindrical core oppositely from the first direction of winding.

Claims

1. A process of winding a filament toroidly onto a hollow cylindrical core, comprising, in combination, the steps of: a. providing a flexible hollow tube which, when the ends thereof are brought together, is rigid enough to form a circular hoop if the tube is otherwise unrestrained but which is flexible enough to accept distortion of said hoop into an elongated noncircular shape; b. loading said tube with a filament in the form of a helix running along the length of said tube; c. inserting said tube through a hollow cylindrical core and bringing the ends of said tube together; d. mounting for rotation and constraining said tube into an elongated non-circular shape with a straight run connected by curved ends, by means of guideS mounted on a frame, at least one of which guides is a rotating drive-guide; e. guiding an end of said filament through a point on the inner periphery of said elongated non-circular shape and restraining said end; f. positioning and mounting said hollow cylindrical core to said frame so that said straight run passes therethrough; and g. rotating said drive-guide and thereby rotating and feeding said tube through said hollow cylindrical core and winding said filament toroidly thereon as the same pays out from said point on the inner periphery.

2. The process of claim 1 comprising in addition:

2. at step (e), guiding an end of the filament of said helix through a second point on said inner periphery; and

3. The process of claim 1 comprising the additional step of: h. during at least part of the winding cycle, reversing the direction of rotation of said tube and winding said filament toroidly onto said hollow cylindrical core oppositely from the first direction of winding.