Helical Coil Forming Machine

Abstract

A pair of large wire supply rolls are rotatably supported by a cantilevered tubular shaft, and corresponding wires extend from the rolls to a coil forming rotor which is also supported by a cantilevered tubular shaft aligned axially with the roll support shaft. Wire is withdrawn from the wire supply rolls by rotation of the rotor which includes precisely driven wheels for feeding the wires through corresponding sets of casting rollers to form a continuous double helix nonrotating coil. A nonrotating mandrel projects through the roll support shaft for supporting the helical coil as it is being formed and progresses axially between a set of endless belts which feed the continuous coil from the coil forming rotor and control the pitch of the wire turns of the coil. A disc brake system is mounted on the roll support shaft for braking the rotation of the wire supply rolls to control the tension in the wires, and the roll support shaft is pivotable in a horizontal direction to facilitate loading of new wire supply rolls into the machine. The machine is also adapted to be used with only one wire supply roll when only a single helix nonrotating continuous coil is required.

Description

BACKGROUND OF THE INVENTION

In the art of producing helical wire coils having convolutions or turns of generally uniform diameter, it is sometimes desirable to provide for producing the coil so that it does not rotate as it is being formed, thereby enabling the coil to be produced in a continuous manner and then fed directly into a secondary operation or wound onto a spool. For example, U.S. Pat. No. 3,118,800 discloses an apparatus for continuously forming a flexible conduit and wherein a nonrotating helical wire coil is fed directly into a tube of foamed plastics material. Nonrotating helical wire coils are also intended to be continuously formed by the machines disclosed in U.S. Pat. Nos. 1,953,502 and 3,541,828. A continuously formed nonrotating helical wire coil may also be fed directly into one or more plastic extruder heads in a manner as disclosed in U.S. patent application Ser. No. 89,333, filed Nov. 13, 1970 and assigned to the assignee of the present invention, for continuously producing a reinforced flexible plastic tube.

For some applications and uses of a wire reinforced flexible plastics tube or conduit, it is desirable to provide for a double wire helical coil so that the wires may be used as electrical conductors along the length of the flexible conduit. For example, U.S. Pat. No. 3,314,039 which issued to the assignee of the present invention, discloses the use of such a conduit in connection with a vacuum cleaner for supplying electrical power to a motor located at the end of a wand which is connected to the vacuum tank by the flexible suction tube. In the production of such a flexible conduit having multiple wire helical reinforcement, it is desirable to provide for continuously producing the conduit to achieve maximum manufacturing efficiency and to minimize the cost of the conduit.

SUMMARY OF THE INVENTION

The present invention is directed to an improved machine or apparatus for continuously producing a nonrotating helical wire coil and which is adapted for forming either a multiple wire helical coil or a single wire helical coil, whichever is desired. The apparatus of the invention also provides for producing a precisely formed helical coil at a high speed and for conveniently loading new relatively large supply rolls of wire into the machine. In general, these features and advantages and other features and advantages which will become apparent from the following detailed description, are provided by apparatus including a cantileveredly supported horizontal tubular shaft which is adapted to support one or more supply rolls of wire for rotation. The shaft also incorporates a brake system for restraining the rotation of the wire supply rolls and is pivotable between a roll loading position and an operating position.

The wire supply roll support shaft is axially aligned with another tubular shaft which supports a coil forming rotor having arms projecting axially outboard of the wire supply rolls to support rollers for directing the wire from the supply rolls to wire feeding and casting means carried by the rotor. As a nonrotating helical wire coil is formed by rotation of the rotor and the wire supply rolls, the coil is formed on and guided by a mandrel initially supported by the supply roll support shaft. The pitch of the wire turns on the mandrel of the continuously formed helical coil, is controlled by a set of angularly disposed endless belts which are driven in adjustable timed relation with the rotation of the rotor. These belts further support the coil and the mandrel on the center of rotation of the rotor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a helical coil forming machine constructed in accordance with the invention;

FIG. 2 is a fragmentary perspective view of a double wire helical coil constructed on the machine shown in FIG. 1;

FIG. 3 is a vertical section generally through the axis of the wire supply support mechanism;

FIG. 4 is a fragmentary elevational view of the wire feed wheels and wire casting rollers forming part of the coil forming rotor shown in FIG. 1;

FIG. 5 is a fragmentary section of the coil forming rotor taken generally on the line 5--5 of FIG. 4;

FIG. 6 is a fragmentary axial section of the helical coil forming rotor shown in FIG. 1; and

FIG. 7 is an elevational view of the left end of the coil forming machine shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The machine of FIG. 1 is illustrated and described for continuously producing a double wire helical coil 15 (FIG. 2) which includes a pair of plastic coated wires 16 formed to produce helical wire turns 18 similar to the double wire helical coil disclosed in above mentioned U.S. Pat. No. 3,314,039. The coil forming machine includes an elongated, fabricated steel base frame 20 on which is mounted a generally C-shaped yoke-like pedestal 22. A block-like support member 24 (FIGS. 1 and 3) is supported by the pedestal 22 for pivotal movement on the vertical axis of a pair of vertically aligned trunion pins 26 (FIG. 3). The member 24 supports one end portion of a horizontally projecting cantilevered tubular shaft 28 having opposite end portions which receive a set of fittings 29 and 31.

The shaft 28 is adapted to receive a pair of spools 32 (FIG. 3) on which corresponding supplies of wire 16 are wound to form a pair of wire supply rolls R (FIG. 1). Each of the spools 32 is rotatably supported by a pair of annular cylindrical bearings 34 which provide for slight axial movement of the spools 32 on the support shaft 28. A set of disc brakes 35 are assembled on the shaft 28 adjacent opposite ends of each spool 32, and the brakes are actuated or compressed axially with the spools 32 by extension of a fluid cylinder 38 connected to a brake yoke member 39 pivotally supported by the support member 24. The roll support shaft 28 and the support block member 24 are adapted to be pivoted on the axis of the pins 26 to a laterally projecting position which provides for conveniently removing the empty spools 32 and for loading a new set of wire supply rolls R onto the shaft 28. When the shaft 28 is returned to its operating position shown in FIGS. 1 and 3, the shaft support member 24 is secured by a lever actuated lock pin 42.

As shown in FIG. 3, an elongated rigid cylindrical arbor or mandrel 45 extends through the roll support shaft 28 and is concentrically supported by the end fittings 29 and 31. The mandrel 45 is extended through the shaft 28 after the shaft is positioned and locked in its operating position shown in FIG. 3. An opening 46 is formed within the rear wall of the pedestal 22 to provide for inserting the mandrel 45 into the shaft 28. The mandrel 45 has a diameter slightly larger than the inside diameter of the helical coil 15 made of plastic coated wire 16 to provide a snug fit of the coil 15 on the mandrel 45 as the coil 15 is being formed.

A coil forming rotor 50 (FIGS. 1 and 6) is supported for rotation by a pair of anti-friction bearings 51 which are mounted on a stationary tubular stub shaft 52. The shaft 52 projects cantileveredly from a housing 54 (FIG. 1) which is mounted on a pedestal 56 secured to the base frame 20. The tubular shaft 52 is axially aligned with the supply roll support shaft 28 in its operating position and receives the concentrically located mandrel 45.

The rotor 50 includes a tubular hub 56 which supports a head plate 58 reinforced by a set of angular bracket members 59. A set of flyer arms 62 project axially from the rotor head plate 58 and are located radially outboard of the wire supply rolls R. Each of the flyer arms 62 supports a corresponding set of guide rollers 64 to provide for directing the wire 16 from each of the supply rolls R to the head plate 58 of the rotor 50.

Referring to FIGS. 4 and 5, the head plate 58 of the rotor 50 supports a pair of diametrically opposed wire feed units 70 each of which includes two sets of wire feed wheels 72 which positively grip the wire received from the corresponding inner guide roller 64. Each of the wires 16 is fed inwardly by the corresponding wheel 72 between a pair of spaced guide shoes 74 and into a corresponding set of casting rollers 76 rotatably supported by an annular plate 77. Each set of casting rollers 76 is arranged to curl or deform the corresponding wire 16 beyond its elastic limit to form a turn 18 around the mandrel 45. The wire turns 18 have substantially no stress so that upon subsequent removal from the mandrel, the coil 15 will maintain its shape.

As shown in FIG. 5, each set of wire feed wheels 72 is mounted on corresponding spindles 78 and 79. Spindle 79 is rotatably supported by a housing 82 forming part of the corresponding wire feed unit 70. Spindle 78 is rotatably supported by an eccentric bushing 83 which permits the use of different diameter feed wheels 72. Each of the housings 82 also supports a gear drive train 84 and a set of change gears 85 which are driven by a planetary gear 86 (FIGS. 5 and 6) engaging a sun gear 88 secured to the rearward or outer end portion of the stationary rotor support shaft 52. The interchangement of different diameter feed wheels 72 and change gears 85, provides for precisely controlling the feed of the wires 16 and for producing coils of different diameters and pitches. The coil forming rotor 50 is driven by a variable speed electric motor 90 (FIG. 1) which has a shaft 91 connected by a pulley 92 and an endless flexible gear belt 93 to a pulley 94 (FIGS. 1 and 6) secured to the cylindrical hub 57 of the rotor 50. An idler pulley 96 maintains a predetermined tension in the gear belt 93.

The double wire nonrotating helical coil 15 is continuously produced or formed on the stationary mandrel 45 by rotation of the rotor 50 in the direction indicated by the arrow in FIG. 1. That is, after the supply rolls R of wire are mounted on the stationary support shaft 28, and the mandrel 45 is extended through the shaft 28 and through the rotor support shaft 52, the wires 16 are directed from the supply rolls R around the corresponding guide rollers 64 to the corresponding wire feed units 70. The wires 16 are initially fed by the feed wheels 72 between the corresponding casting rollers 76, by manually rotating or jogging the rotor 50.

After the wires 16 are started, and rotation of the rotor 50 continues, the pair of wires 16 are positively and simultaneously fed inwardly at a rate which corresponds to the length of each turn 18 with each revolution of the rotor so that the double wire helical coil 15 fits snugly on the mandrel 45 with substantially no stress in the wires 16. As the rotor 50 rotates on the shaft 52, the pull on the wires 16 causes the wire supply rolls to rotate on the shaft 28 at a speed or rate which is slightly greater than the rotational speed or rate of the rotor 50. This additional rotational speed of the wire supply rolls R is due to the fact that with each revolution of the rotor 50, a length of wire 16 corresponding to the length of a helical turn 18, is unwound or pulled from each of the supply rolls R. The tension in the wires 16 from the supply rolls R to the wire feed wheels 72 is controlled by actuation of the brake cylinder 38.

As the nonrotating helical coil 15 is formed on the mandrel 45 and moves forwardly through the tubular stationary rotor support shaft 52, the nonrotating helical coil 15 is gripped by a coil feeding mechanism 100 (FIG. 1). The coil feeding mechanism 100 includes a series of three endless flexible V-belts 102 which are uniformly arranged around the mandrel 45 (FIG. 7). Each of the belts 102 is directed around a set of inner pulleys 104 and a larger outer pulley 106. The inner pulleys 104 of each set are arranged to provide an inner axial run of the corresponding belt 102 for frictionally engaging the outer surface of the nonrotating helical coil 15. Each set of pulleys 104 and 106 are supported by a corresponding axially extending radial plate 108 which is radially adjustable relative to a stationary frame member 110 by adjustment of a corresponding screw 112.

Referring to FIG. 7, one of the pulleys 104 of each set of pulleys, is mounted on a shaft which also supports a pulley 116. An endless V-belt 118 is directed around the pulleys 116 and a set of guide pulleys 119. Another pulley 123 is mounted on the shaft which supports the upper pulleys 104 and 116, and an endless flexible V-belt 124 is directed around the pulley 123 and a set of guide rollers 126 (FIG. 1) to a pulley 127 mounted on the output shaft of a gear reducer 128. The input shaft of the reducer 128 is connected to the motor shaft 91 through a speed variator 132 and a set of couplings 133.

By adusting the speed of the variable speed reducer 132, the speed of the belts 102 is adjusted to change the pitch of the wire turns 18 of the nonrotating helical coil 15 as it is being produced by rotation of the rotor 50. However, a change in the speed of the motor 90 to increase or decrease the speed of forming the helical coil 15, automatically changes the speed of the coil feed belts 102 so that the preselected pitch of the wire turns 18 remains constant.

From the drawings and the above description, it is apparent that a helical coil forming machine constructed in accordance with the present invention, provides desirable features and advantages. For example, the machine provides for continuously and rapidly producing a multiple wire nonrotating helical coil from large supply rolls. The machine is also adapted for producing a single wire helical coil, simply by feeding only one wire 16 into the rotor 50 and between one set of casting rollers 76. As a series of mandrels 45 or discrete sections of mandrels are fed in end-to-end abutting relation through the wire supply roll support shaft 28, the mandrels provide for guiding the continuously formed helical coil between the coil feed belts 102 to assure that the coil is positively fed from the coil forming rotor 50 as the coil is formed. In addition, the speed of the coil feed belts 102 may be infinitely controlled relative to the speed of the rotor 50 by adjusting the speed variator 132 so that the pitch of the helical turns 18 may be conveniently changed and precisely set while the nonrotating coil is being produced.

Another important feature is provided by the support of the wire supply roll support shaft 28 for pivotal movement between its normal operating position (FIG. 1) and a laterally projecting loading position where empty spools 32 may be conveniently removed and new wire supply rolls R may be conveniently mounted on the shaft 28. Furthermore, the disc brakes 35 cooperate with the wire supply rolls R when the brakes are energized by actuation of the cylinder 38 to prevent overspinning of the wire supply rolls R and to control the tension within the wire 16 extending from the supply rolls to the coil forming rotor 50. The wire feed units 70 also cooperate to force the corresponding wires 16 inwardly between the corresponding set of casting rolls 76 to deform each of the wires into the desired radius of curvature substantially conforming to the diameter of the mandrel 45.

While the form of coil forming apparatus herein described constitutes a preferred embodiment of the coil forming invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope and spirit of the invention. For example, the machine could be easily modified to form a continuous nonrotating triple wire helical coil, for example, if it were desirable to add a ground wire within a flexible plastic conduit requiring two electrically conducting wires.

Claims

The invention having thus been described, the following is claimed:

1. Apparatus for continuously producing a nonrotating coil having helical wire turns of substantially uniform diameter, comprising a coil forming rotor including means for receiving a wire and for deforming the wire beyond its elastic limit into continuous wire turns, first shaft means for supporting said rotor for rotation on an axis, drive means for rotating said rotor, second shaft means for supporting a supply roll of wire on an axis substantially aligned with the axis of rotation of said rotor, means on said rotor for directing the wire from the supply roll to said wire deforming means, and means for guiding the coil axially from said rotor as the coil is formed by rotation of said rotor.

2. Apparatus as defined in claim 1 wherein said second shaft means comprises an elongated tubular shaft, and means for supporting a mandrel for axial movement within said tubular shaft.

3. Apparatus as defined in claim 2 wherein said means for driving said rotor include a motor, a plurality of endless feed belts positioned to engage the helical coil at circumferentially spaced intervals and press the coil against said mandrel, and means connected to said motor for driving said belts in timed relation with the rotation of said rotor to effect positive axial feeding of the coil and said mandrel from said rotor.

4. Apparatus as defined in claim 1 wherein said second shaft means comprises an elongated shaft, and means supporting said shaft for lateral movement between a wire roll loading position and a coil forming position in axial alignment with the axis of said rotor.

5. Apparatus as defined in claim 1 wherein said rotor includes at least one flyer arm extending generally parallel to the axis of rotation of said rotor and located radially outboard of the supply roll.

6. Apparatus as defined in claim 1 wherein said first shaft means for supporting said rotor comprise a tubular shaft, and the coil is directed axially through said shaft as the coil is formed.

7. Apparatus as defined in claim 1 including means for variably braking the rotation of the wire supply roll as the supply roll rotates in response to rotation of said rotor.

8. Apparatus for continuously producing a nonrotating coil having helical wire turns of substantially uniform diameter, comprising a coil forming rotor including means for receiving a wire and for deforming the wire beyond its elastic limit into continuous wire turns, a tubular shaft supporting said rotor for rotation on an axis, drive means for rotating said rotor, means for supporting a supply roll of wire on an axis substantially aligned with the axis of rotation of said rotor, means on said rotor for directing the wire from the supply roll to said wire deforming means, and means for feeding the coil axially through said tubular shaft supporting said rotor as the coil is formed by rotation of said rotor.

9. Apparatus as defined in claim 8 wherein said means for supporting a supply roll of wire include a second tubular shaft, and means on said second shaft for supporting a mandrel in a position projecting axially into said tubular shaft supporting said rotor.

10. Apparatus as defined in claim 9 including means supporting said second tubular shaft for lateral movement between a wire roll loading position and a coil forming position in axial alignment with said shaft supporting said rotor.