US3478408A

US3478408A - Method and apparatus for forming helical springs and the like

Info

Publication number: US3478408A
Application number: US499374A
Authority: US
Inventors: Kenard Daniel Brown
Original assignee: Kenard Daniel Brown
Current assignee: SWANTON WILLIAM F
Priority date: 1965-10-21
Filing date: 1965-10-21
Publication date: 1969-11-18
Anticipated expiration: 1986-11-18

Description

K. D. BROWN Nov. 18, 1969 METHOD AND APPARATUS FOR FORMING HELICAL SPRINGS AND THE LIKE 6 Sheets-Sheet 1 Filed Oct. 21, 1965 INVENTOR. Kenard D. Brown I i g o 2 BY jfi ATTORNEYS Nov. 18, 1969 K. D. BROWN 3,478,408

METHOD AND APPARATUS FOR FORMING HELICAL SPRINGS AND THE LIKE Filed Oct. 21, 1965 6 Sheets-Sheet 2 IF 9- Fig.6

EELS/-70 INVENTOR. 70 Kenard D Brown Tig-IO ATTORNEYS Nov. 18, 1969 K. D. BROWN 3,478,408

METHOD AND APPARATUS FOR FORMING HELIGAL SPRINGS AND THE LIKE Filed 001;. 21, 1965 6 Sheets-Sheet 5 12 INVENTOR. -E- Kenard D. Brown ATTORNEYS Nov. 18, 1969 K. D. BROWN 3,478,408

METHOD AND APPARATUS FOR FORMING HELICAL SPRINGS AND THE LIKE 6 Sheets-Sheet 4 Filed Oct. 21, 19 65 IN VEN TOR.

KENARD D. BROWN ATTORNEYS Nov. 18, 1969 K. D. BROWN 3,478,408

METHOD AND APPARATUS FOR FORMING HELICAL SPRINGS AND THE LIKE Filed Oct. 21, 1965 6 sheets-Sheet 5 INVENTOR.

KENARD D. BROWN ATTORNEYS Nov. 18, 1969 K. D. BROWN 3,478,408

METHOD AND APPARATUS FOR FORMING HELICAL SPRINGS AND THE LIKE 6 Sheets-Sheet 6 Filed Oct. 21, 1965 INVENTOR. KENARD D. BROWN ATTORNEYS United States Patent U.S. Cl. 29458 23 Claims ABSTRACT OF THE DISCLOSURE A method for producing a helical coil of wire comprises drawing a wire continuously across a deflector and pressing it into engagement therewith to produce a curl in the wire about an axis on the same side of the wire as the deflector and then guiding the Wire into a helical coil about a longitudinal axis. The longitudinal axis may be that of a cylindrical tube about which the coil is wrapped. The method may further include passing the wire over spaced deflectors the first to bend the wire away from and the second toward the longitudinal axis.

An apparatus on which the method may be practical comprises a rotatable wire supply and forming assembly having a hollow center shaft through which a plastic tubing or the like may be fed for wrapping with a helical coil of wire. The wire is fed through a tool on the rotating assembly and onto the tube about which the assembly is rotated. The tool comprises spaced deflecting elements arranged first to bend the wire away from the tube and then toward the tube. The tool rotates about the tube close to its surface and the bend away from the tube occurs nearer the center of rotation than the subsequent bend toward the center. The apparatus produces continuous lengths of helical wire wrapped tubingthe wrapping may be made to lie merely in contact with the surface of the tubing or to grip it.

This is a continuation-in-part of copending application Ser. No. 225,559 filed Sept. 24, 1962, now abandoned.

This invention relates to the manufacture of helically wound spring wire products and particularly to an improved method and apparatus for continuously forming helical springs and for Wrapping such springs on tubing or the like.

Many applications requiring helically wound spring wire make it desirable to provide long or greatly extended continuous lengths of the helical spring. For example, it is desirable to provide long continuous lengths of tubing having thereon a helical Wrapping of wire to provide increased resistance to internal pressure and to external crushing forces, and it has been found diflicult to provide such wrapping in a manner such that it will remain in its required relationship to the tube when the tube is cut to desired lengths during installation or use. In other applications of helical springs it is desirable to provide an insulating or protecting coating on the spring which must be of uniform thickness and insulating quality. Various methods and apparatus have been proposed to overcome these problems but these have not been found entirely satisfactory for all applications. Accordingly, it is an object of the present invention to provide an improved method for manufacturing helical springs in continuous lengths.

It is another object of this invention to provide an improved method for making insulation coated helical springs.

It is still another object of this invention to provide an improved method for forming a helical wrapping of reinforcing wire such as spring wire in firm engagement about a tube or other cylindrical structure.

It is a further object of this invention to provide an lmproved apparatus for forming helical wire springs and similar wire structures.

It is a further object of this invention to provide a simple and improved apparatus for making insulation coated helical springs.

It is a still further object of this invention to provide an improved apparatus for wrapping a helical layer of reinforcing wire on a tube or other cylindrical structure.

Briefly, in carrying out the objects of this invention in one adaptation thereof, a length of wire is first coated with a uniform layer of plastic, such as nylon, or other tough insulating material. The wire is then driven forward transversely toward the axis about which a helical coil is to be formed. At a desired radial distance from the axis the wire is bent through a slight S or ripple-curve away from and then toward the axis and is thereby coiled about the axis; by rotating the wire about the axis as it is driven toward it, the coil may be maintained stationary about the axis. By providing a cylindrical mandrel or body, such as a continuous plastic tube, the coil may be formed about the body in continuous firm contacting engagement or if desired in gripping engagement provided that the body has a diameter somewhat greater than that of the internal diameter of the coil if it were allowed to form as a free sprmg.

The apparatus of this invention in one embodiment thereof comprises a forming unit rotatably mounted on a hollow cylindrical support and having a tool holding plate extending beyond the end of the support. A supply spool of the plastic coated wire to be used is mounted for free rotation around the cylindrical support in a position to be fed to the coil forming mechanism. The machine is arranged to drive the Wire toward a tool mounted on the holder and spaced radially from the axis of rotation. The tool is arranged to provide a plurality of spaced steps or diverter points which introduce an S-curve in the wire which bends first away then toward the axis and which produces the required circular turn of the helix. The tool holder and tool are rotated about the axis at a rate correlated with the feed rate of the wire so that the coil is formed and retained stationary about the axis.

The features of noveltywhich characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. The invention itself, however, both as to its method of operation and its organization together with further objects and advantages thereof will be better understood upon reference to the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view partly cut away showing a spring forming machine embodying the invention;

FIG. 2 is an enlarged longitudinal sectional view of a portion of the device taken along the line 2-2 of FIG. 1;

FIG. 3 is an enlarged diagrammatic view illustrating the gearing for driving the wire feed;

FIG. 4 is a side elevation view of a tube wrapping equipment provided with a spring forming machine of the type illustrated in FIG. 1;

FIGS. 5 and 6 are side and front elevation views, respectively, of a wire shaping tool for the machine of FIG. 1;

FIG. 7 is a perspective view of the tool illustrated in FIGS. 5 and 6;

FIG. 8 is an enlarged end view of the spring forming tool of the apparatus of FIG. 1;

FIGS. 9 and 10 are side and front elevation views, respectively, of a portion of a tool similar to that of FIGS.

5 and 6 provided with an attachment for controlling spacing of the turns of the wire helix;

FIG. 11 is an enlarged top view of the attachment of FIGS. 9 and 10;

FIG. 12 is an enlarged view of the operating end of the tool of FIG. 8;

FIGS. 13 and 14 are rear elevation and side views, respectively, of the operating end of a modified form of the tool;

FIG. 15 is an end view similar to FIG. 8 illustrating a modification of the apparatus of the invention;

FIG. 16 is a side elevation view partly in section and partly broken away of the tool holding assembly of FIG. 15;

FIG. 17 is an enlarged end view of the lower end of the tool illustrated in FIG. 15;

FIG. 18 is an enlarged end view similar to FIGS. 8 and 15 illustrating a further embodiment of the invention;

FIG. 19 is an enlarged side elevation view of a portion of the assembly of FIG. 18;

FIG. 20 is a sectional view of an extruding apparatus illustrating a step in one method of the invention;

FIG. 21 is a side elevation view partly broken away diagrammatically illustrating a modified form of winding equipment embodying the invention; and

FIG. 22 is an end elevation view partly broken away and partly in section of a portion of the apparatus of FIG. 21 taken along the line 2222 of FIG. 21.

Referring now to the drawings, the invention has been illustrated, by way of example, in FIG. 1 as embodied in a spring forming unit 10 mounted on a rigid stand 11 having a base 12 and arranged to provide a coiled spring 13 wrapped tightly about a thin plastic tube 14 which is fed through a central passage in the unit 10. The assembly 10 includes a cylindrical support 15 rigidly and securely attached to the base column 11 and having a ring or sun gear 16 rigidly secured to its opposite end. A tool holding assembly 17 is mounted on a cylindrical shaft 18 for rotation within the cylindrical support 15. In order to facilitate the rotation of the shaft 18 it is mounted in roller bearings 20 and 21 at either end of the cylindrical support 15. The shaft 18 is provided with a pulley 22 which may be driven by a belt connected to a suitable driving motor (not shown). The tube 14 on which the coil spring is to be wrapped passes through the shaft 1 8 and is freely slidable axially of the shaft on

inner rings

23 and 24 of

ball bearing assemblies

25 and 26 mounted at respective ends of the shaft 18, the assembly 26 being shown in FIG. 2.

In order to provide a supply of the wire from which coiled spring is to be formed, a spool 28 is mounted about the support 15 on ball bearing assemblies 29 and 30 so that the spool is free to rotate about the support 15. The wire is fed to a wire drive mechanism 31 from the spool 28 as indicated at 32, the wire portion 32 passing from the spool through an eye 33 at the end of a bracket 34 rigidly attached to the tool holder assembly 17.

The drive assembly 31 for the unit is arranged to force the wire through two sets or pairs of

rollers

35 and 36 and thence through a tool 37 which forms the wire to provide the coil 13, the wire passing from the tool 37 in a low loop 38 which is of a radius of curvature such that it falls into place about the tube 14 and grips the tube tightly. The wire is formed by the tool 37 so that if the tube were not present it would be formed as a free coil of a diameter slightly less than that of the external diameter of the tube. In some applications of this machine and process the wire is bent so that it just fits about the wall of the tubing, its internal helix diameter being essentially the same as the external diameter of the tube.

The driving

wheels

35 and 36 are connected to be driven from a planet gear 40 which is mounted on a shaft journaled in the plate or tool support 17 and engages the sun gear 16 so that as the shaft 18 is rotated the gear 40 is driven at a rate determined by the ratio of the pitch diameters of the

gears

16 and 40. The pairs of gears for driving the respective pairs of

drive wheels

35 and 36 are arranged as shown in FIG. 3, both pairs of gears being driven from a driving pinion 41 which is connected directly to the gear 40 through its shaft 42.

It will now be seen that the gears of the

pairs

35 and 36 are rotated so that the driving wheels associated therewith are driven in pairs in the same direction. Thus a wire passing through the pairs of drive wheels, as indicated by the arrow in FIG. 3, will be driven from left to right. 7

The wire 32 on the spool 28 may be either bare or coated; however, in this example it is illustrated as coated, it having been formed by providing a uniform coating of a tough smooth cover such as nylon, the covering being formed to a substantial thickness. For example, the cover may have a thickness of the order of one-fourth the diameter of the wire. The thickness of the covering depends upon the material used and is not critical; however, it is selected to provide adequate insulation or adequate abrasion resistance of the wire and is made of a material and of a thickness sufficient to assure its being maintained intact and uninjured throughout the operations of the forming equipment. Not only does the covering provide the desired protection of the wire, but it also serves as a lubricant during the passage of the wire through the forming tool 37. The pairs of

drive wheels

35 and 36 urge the wire toward the tool 37 and force it through the tool to alter its configuration and form the coil in a manner to be described hereinafter.

At the same time that the wire is being fed toward the tool 37, the entire assembly is of course being rotated by rotation of the shaft 18. The rate of feeding of the wire is selected with respect to the speed of the shaft 18 so that the wire is wrapped around the tube 14 at a rate such that the tube and wire coil 13 do not rotate but remain stationary about their longitudinal axis during the operation of the equipment; thus the tube need only be moved axially as the coil is formed. This provides a secure and firm pressure resisting wrapping about the tubing 14 and continuous lengths of tubing may be passed through the equipment and wrapped with wire. Furthermore, the wire will remain in place at the end of the tubing and also, should the tubing be cut into separate lengths, the wire in each length will remain in place fitting closely about and, if desired, tightly gripping the exterior walls of the tube. If the tubing is omitted the wire will be formed in a continuous helical free coil of a diameter which is normally somewhat less than that of the tubing; thus a plastic coated spring may readily be formed to the diameter selected by the position of the tool 37.

When bare spring wire is employed, it may be desirable to provide a lubricant to facilitate the forming operation and assure uniform coiling of the final product. Although plastic coatings are desirable for a wide range of applications, various other coatings lend themselves to use in this method of forming spring and other wire structures. For example, metallic coatings and metalimpregnated plastic coatings may be employed.

The helical wire coil or spring forming assembly or unit 10 illustrated in FIG. 1 and as just described may be incorporated in an equipment for producing continuous helical coil reinforced tubing as shown in FIG. 4. In this figure the drive pulley 22 has been shown connected by a belt 44 to be driven by an electric motor 45 and the reinforced tubing, after passing from the unit 10, has been shown as drawn through a drive roll 46 and idler roll 47 onto a collecting drum 48 which is mounted for rotation in a supporting base 50 and is driven by a suit able motor (not shown). The drive roll 46 is driven by a motor 51 mounted in a base and supporting structure 52. The motor drives the roll 46 through a belt 53 and the idler wheel 47 is mounted on top of the wheel 46 in position to engage the tubing 13 and press it downward to maintain it in good driving engagement with the drive wheel.

The configuration of the tool 37 is clearly shown in FIGS. 5, 6 and 7. The tool as illustrated comprises a main body portion 54 and a shank 55 of reduced cross section which is provided with an elongated slot 56 having sides parallel to the sides of the tool. The lower end of the tool is rounded at one side as indicated at 57 and has a short extension 58 at its other side. The extension 58 is formed with a straight length of groove or guide 60 having a cross-sectional diameter slightly greater than that of the wire to be used with the tube. As illustrated the groove lies closely adjacent the lower end of the tool and only a thin strip or section of the tool, indicated at 61, extends beyond the groove 60. The groove 60 opens forward and hence axially of the shaft 18 and its curved or circular cross section, as indicated in FIG. 5, is such that the wire is retained in position against displacement from the groove axially of the shaft 18. The slot 56 is provided in order that a bolt, indicated at 62 in FIG. 1, may be employed to clamp the tool rigidly to the tool holder 17.

The arrangement of the tool and its position during operation may more readily be understood from FIG. 8 which is an enlarged view with the curvature of the wire passing through the tool somewhat exaggerated for purposes of illustration.

As clearly shown in FIG. 8, the tool 37 is mounted so that the left-hand edge of the portion 61 is closely adjacent and in some applications touching the outer surface of the tube 14. This brings the entrance edge of the groove 60 close to the tube. The wire 32 is fed or forced forward by operation of the pairs of

rollers

35 and 36, the pair 36 being shown in FIG. 8, and as the wire moves forward -it strikes the near or lower rounded edge portion 57 of the tool and enters the groove 60 and is curved downwardly over the lower edge portion or knee 57 so that it takes a curved or bowed configuration about as shown by the portion 65. As previously stated, the groove 60 is of a width slightly greater than the diameter of the wire 32 and the configuration of the wire as it passes through the tool is in S or reentrant form, the wire moving from the knee 57 to the bottom of the rear corner or leaving edge of the groove 60, presents a small radius or edgelike shoulder and produces a reverse bend as indicated at 66. The bend 66 has been shown of somewhat exaggerated curvature, its radius having been shortened for emphasis; however, it will be noted that it is in a direction such that the wire tends to coil about the tube 14 as indicated. The bend 66 is produced at the edge or shoulder of the portion 61 and results from plastic deformation at the edge, the elastic limit of the wire being passed at this edge due to the pressure of the wire against the edge. The change in curvature is abrupt at the edge and the wire curves outwardly away from the shoulder in a curve which then turns back toward the tube 14 on which it is being wrapped. The forming pressure against the edge 61 is applied by the urging of the Wire against the shoulder by the portion 57 on one side and the engagement of the wire and the tube 14 on the other side. The angle of the tool 37 causes a torque to be exerted on the wire between the

shoulders

57 and 61. 'It will be observed that the pressure exerted between the shoulder 61 and the wire may be changed by changing the angle of the tool 37 to change the position of the line between the

shoulders

57 and 61. Thus, the degree of bending of the wire may be adjusted.

Under some conditions of operation when relatively large wires are being employed, the wire after bearing on the rounded edge 57 may be forced against the rear or entrance edge of the groove 60 and thereby be curved upwardly away from the rear or departing edge of the strip 61 and may engage the upper corner of the tool 37 opposite the curved edge 57 which provides a guiding and curve modifying function which may facilitate the operation of the tool to guide the wire into the desired helical coil configuration. It will be understood that for this type of operation it may be desirable to change the relative proportions of the two shoulders or parts of the tool to secure effective use of the edge or shoulder portions in the manner just described. A tool for more effectively securing'these functions is shown in the drawings in FIG. 15 and described below.

The internal diameter of the free coil formed by the tool without the tube 14 present would be of no greater than and normally would be somewhat smaller than the outer diameter of the tube, and, as a consequence, the coiled wire lies in engagement with the tube and normally grips the tube tightly as it moves along. The wire may be laid in closely adjacent coils, the coils touching each other as they are wound around the tube, or by increasing the rate of movement of the tube it may be spaced at a predetermined pitch selected by adjustment of the axial speed of the tube.

The driving engagemnt of the

rollers

35 and 36 on the wire 32 may be adjusted by a nut 68 which varies the position of a movable element 69 on which the upper rollers are mounted. The range of this adjustment is relatively small, it being limited by the range of radial movement afforded by the gear teeth for driving the rollers, a certain relative movement of the teeth being possible without interfering with their operation.

It will be understood that the diameter of the coil formed by applicants method as illustrated in the operation of the device shown in FIG. 8 may be varied by employing a tool 37 having different relative positions of the two contact points which the wire makes with the tool and by changing the angle of the tool to vary the point of engagement of the wire with the tube and, also, by changing the dimensions of the groove 60 to accommodate the particular size of Wire to be employed. The tube, in effect, acts as a third stop or control element for determining the final configuration of the wire.

Apparatus embodying the invention as illustrated has been operated continuously both with and without the use of a tube 14 and has been employed to make both the reinforced tubing and the springs produced when the tubing is omitted. The wrapping on the tubing and the coils of the springs were of uniform diameter and spacing regardless of the length of the coil or spring produced. It was found that the spring wire could be wrapped continuously onto the tubing in gripping engagement without exceeding the elastic limit of the wire material after it leaves the forming tool and winds around the tube.

When employing the method of this invention for producing coiled helical springs, it may be desirable to form the springs with a predetermined spacing between adjacent turns of the coil. For the purpose of producing springs in this manner as distinguished from tightly coiled springs, a tool as indicated in FIGS. 9, 10 and 11 may be employed. This tool is of the same construction as that of the tool of FIGS. 5, 6 and 7 with the addition of an attachment 70 which is secured to the lower end of the tool by a suitable machine screw 71 as illustrated. The attachment 70 closes the open face of the groove 50 and extends beyond the tool a substantial distance toward the axis of rotation. The attachment 70 is a wedge, as clearly indicated in FIG. 11, and as the tool moves about the'axis the coil formed by the operation of the tool is caused to pass on the outside of the wedge 70 so that the coil is separated as it is formed and the pitch of the turns is predetermined by the dimensions of the attachment 70, each turn of the coil being forced away axially from the next and not returning to a position of engagement with adjacent coils.

It has been found that a tool of the construction of the tool 37 may be employed effectively for the coiling or wrapping of wires of relatively small diameter; for example, a wire having a diameter of less than one-fourth of that illustrated in FIG. 8 may be wound eifectively about a tubing by operation of the apparatus. For this type of application the angle of the tool is adjusted by rotation of the tool about the pivot bolt 62 so that effective bending and coiling of the wire may be accomplished.

When wires of the size illustrated in FIG. 8 are employed and pass through the tool along the curve indicated, the wire is pressed firmly against the leaving edge of the tool portion 61 and this pressure tends to produce a momentary depression in the surface of the wire as it moves in frictional engagement with the edge. In FIG. 12 the end of the tool 37 is illustrated in an enlarged view, the portion of the wire passing through the tool in an elongated S-curve as shown and for this operation bearing solely against the rounded corner 57 and the leaving edge of the tool portion 61, the wire tending to be indented temporarily at the zone indicated at 75 and being plastically deformed at this point. The frictional engagement produced by the downward pressure of the wire against the rounded right-hand end of the section 61 of the tool produces the curving of the wire indicated at 66 wherein the wire is curved toward the axis about which it is to be coiled, normally at a radius somewhat less than the tubing or other cylindrical body about which it is to be wound. This curve, as stated before, has been somewhat exaggerated in FIGS. 8 and 12, the reverse curve occurring immediately upon the passing of the wire over the leaving edge of the tool strip 61.

A tool such as the tool 37 may be constructed to carry a plurality of wires which are then Wrapped in adjacent helical configuration about a tubing such as the tube 14. The working end of a tool of this type is shown in FIGS. 13 and 14 which illustrate a tool 76 provided with a portion 77 of reduced cross section similar to the extension 58 of the tool 37. The tool 76 provides a rounded shoulder or stop 78 corresponding to the shoulder 57 of the tool 37, and the wire guide corresponding to the groove 60 of the tool 37 comprises a hole or opening 80 extending through the extension 77 and having its lower wall portion provided with two

guide grooves

81 and 82 for receiving two wires to be passed through the tool in parallel. Tools providing a greater number of such guide grooves may, of course, be provided if more than two wires are to be wrapped simultaneously about a cylinder or mandrel.

The operation of the tool of FIGS. 13 and 14 is essentially the same as that of the tool 37 previously described, the two wires being driven through the tool together and first engaging the rounded edge 78 and then passing through the

grooves

81 and 82 and over the far or leaving edge of the recess 80.

FIG. illustrates a modified form of the tool which is arranged to facilitate the adjustment of the stop or guide points or shoulders to provide the adjustment required for various sizes of wire and diameters of the coil to be formed. In this figure parts corresponding to the parts of the apparatus shown in FIG. 8 have been designated by the same numerals with the addition of the suffix a. The tool 37a is mounted on a plate 83 which extends radially outwardly in a plane transverse to the axis of the coil or spring to be formed. The plate 83 is mounted on the tool holding assembly 17a on a ring 84 concentric with the central axis of the assembly and formed in the face of the tool support as indicated at 85 in FIG. 16. The tool 37a is provided with a slot 56a through which a mounting bolt 62a is passed. This bolt also passes through a circular opening 86 in a plate 87 which is secured to the plate 83 when the tool 37a is bolted against the plate. The plate 87 carries a shoulder or bar 88 which terminates in a rounded guide stop or shoulder 90.

It will now be seen that because of this mounting the tool 37a and plate 87 may be adjusted with respect to one another and with respect to the plate 83. In order to effect angular adjustment of the tool 37a about the pivot bolt 62a, a pair of adjusting

screws

91 and 92 are provided which are threaded in

lugs

93 and 94, respectively, rigidly attached to the plate 83. The wire to be coiled, indicated at 32a, is passed through the tool 37a in a manner essentially the same as indicated for the wire 32 in FIG. 8 and then the curved portion 66a as it leaves the tool engages the shoulder and its curve is modified to conform to a required coil diameter. The shoulder 90 constitutes a guiding element and performs the function of cooperating with the shoulder 57a and urging the wire against the edge of shoulder of portion 61a of the tool 37a. Thus the shoulder 90 performs the functions of the tube 14 in the embodiment of FIG. 8. It has been found that this form of the tool when adjusted to the size of wire and required curvature of the coil provides accurate formation of free coils or springs, and the assembly as illustrated in this figure is provided with a circular closure plate 97 which covers the central passage through the machine. This plate may be moved outwardly to the left as viewed in FIG. 16 to provide a short or stub mandrel about which the initial coil or coils of the spring are formed. For some applications the use of the sub mandrel has been found to facilitate the securing of an accurately formed spring.

The adjustment of the tool assembly to the required wire size is facilitated by the mounting arrangement of the ring 84 in the groove 85 so that the angle of the plate 83 may be adjusted with respect to the feed fire 32a. When the desired angle has been determined the ring may be locked in place by tightening bolts 95 threaded in the assembly 17a and which press washers 96 against the ring.

FIG. 17 is an enlarged end view of the tool 37a illustrating wire passing through the tool. In this figure the tool is shown in section and it can be seen that the bottom wall portion of the wire passage 60a is formed to provide a section which is of decreasing thickness rearwardly. The tool 37a has been illustrated as provided with a closed wire passage similar to the passage in the tool of FIGS. 13 and 14 rather than the open passage of the tool 37 of FIG. 8. The wire passing through the tool 37a first engages the rounded rear shoulder of the tool indicated at 57a and then the forward edge or shoulder of the portion 61a indicated at 97. The action of the wire and the change in its configuration are essentially the same as that effected by operation of the tool 37 of FIG. 8.

Another arrangement of the bending tool of this invention is illustrated in FIGS. 18 and 19. In these figures parts of the assembly corresponding to parts of the assembly of FIG. 8 have been designated by the same numerals with the addition of the suffix b. In this tool assembly two stop members or pins 100 and 101 are provided and are rigidly mounted on a tool assembly comprising a plate 102 mounted on a ring 103 in a manner similar to the mounting of the plate and

ring

83 and 84 of FIG. 15. The plate 102 carries an adjustable bar 104 which carries the stop 100, and the stop 101 is secured directly to the plate 102 in a position adjacent the edge of the central opening within which the tube 14b is carried.

A wire indicated at 3217 is passed through the driver assembly 36b and moves through a curved portion 6512 against the stop 100 which act in the same manner as the shoulder 57 of FIG. 8. It is then carried forward to pressing engagement with the stop or shoulder 101 where it is bent outwardly in a manner similar to the wire passed through the assembly of FIG. 8 and forms a curve as indicated at 6612. The construction illustrated in FIGS. 18 and 19 provides a simplified arrangement which has been found effective for use particularly when larger diameters of wire are to be wound.

In all of the tool assemblies illustrated it may be desirable to provide a coating of smooth tough plastic material, as indicated before, and FIG. 20 indicates a type of extruding head suitable for this purpose. In heads such as illustrated there is provided a heavy metal body indicated at 106 and in which a fluid material passage 107 is provided in communication with a tapered or conical 9 chamber 108 in which a wire feeding guide 109 is centered. A wire 110 is fed through the guide 109 and the plastic material extruded onto the wire to form a layer as indicated generally at 111.

This type of extrusion apparatus is capable of producing a very smooth plastic coating on a wire, the coating being cured as it leaves the die and before it is coiled on a suitable reel. The thickness of the coating may be varied by changing the extruding die indicated at 112, and various diameters of wire may be employed, a guide 109 having a suitable diameter passage for the wire being selected for this purpose.

While the wire wrapping or coiling devices described above have all been illustrated with arrangements for moving the tool about the tubing to be wrapped or spring to be formed so that the tubing or spring does not rotate, the apparatus of this invention is also useful for wrapping or mandrels, tubing or conduit wherein the tubing is rotated while the tool remains in a stationary position.

- Apparatus such as this has been found useful for wrapping predetermined lengths of large diameter tubing or conduit and an apparatus for this purpose is diagrammatically illustrated in FIGS. 21 and 22.

In these figures a tubing or conduit indicated at 115, and which is to be wrapped with a wire to provide a wrapped conduit as indicated at 115' to the left of a tool 116, is mounted in a hollow-shafted lathe having a driving head 117 through which the finished product passes and having one or more rests 118 for holding the tubing 115 in alignment. The tool 116 is mounted on a carriage or tool carrier 120 which is mounted for movement along a bed 121 on rails or guides 122. The carrier is provided with an extension 123 which is mounted for sliding movement along the lathe bed indicated at 124. The carrier 120 is provided with a tool mounting bracket or plate 125 on which the tool 116 is mounted and with respect to which it may be adjusted by loosening a bolt 126 in the same manner as the adjustment of the bolt 62, for example, in FIG. 8.

The wire to be wrapped about the tubing 115 is carried on a reel 127 mounted on bearing

brackets

128 and 129 secured to the carrier 120, the reel having been broken away in FIG. Q1 to show the tool assembly. The wire after passing from the reel goes through a guide loop 130 and thence onto the tool, it being drawn through the tool by rotation of the tubing 115 effected by rotation of the lathe head 117. The carrier 120 is moved along the bed 124 at a rate to secure the required positions of the turns of the wrapping 115, the movement of the carriage being effected by operation ofa longitudinal screw 131 in a manner well known in the lathe and machine tool art.

The mechanisms of FIGS. 1 and 21 are illustrative of two methods of applying the driving forces to the wire, the apparatus of FIG. 1 driving the wire into the tool and that of FIG. 21 drawing it through the tool by rotation of the tubing.

It will be apparent from the foregoing that this invention provides a simple and effective arrangement for forming wire in helical coils and particularly for wrapping a helical winding about a tube or conduit in a manner such that the wire remains in position and does not tend to be displacedeven though the conduit is cut or broken. The wire may be wrapped tightly in gripping engagement about the conduit or, if desired, may be wrapped so that it contacts the surface of the conduit but does not grip the conduit. The type of wrapping to be secured, of course, depends upon the applications for which the wrapped tubing or conduit is intended, and the degree of gripping engagement of the wire and the tubing may be; varied depending upon the use or application of the conduit. For example, a tighter gripping wrapping may be desirable when the tubing is required to resist high pressures.

The method and apparatus of this invention have a further advantage in that wire regardless 'of diameter may be coiled tightly to form a spring or helical wrapping or may be wrapped tightly about a cylindrical form such as a tube without damaging the wire. For example, a large diameter wire may be coiled about a small tube without substantial expansion or rotation upon release of the wire and without injury to the wire which might otherwise decrease its strength and render it ineffective for its purpose, and so-called normalizing becomes unnecessary.

While the method of this invention has been described in connection with the operation of specific forms of apparatus embodying the invention, various other applications and modifications of the method of the apparatus will occur to those skilled in the art. Therefore it is not desired that the invention be limited to the specific details illustrated and described and it is intended by the appended claims to cover all modifications which fall within the spirit and scope of the invention.

I claim:

1. An apparatus for the continuous production of helically coiled spring wire or the like which comprises a unit mounted for rotation about a fixed axis, said unit comprising a tool holder mounted for rotation about said axis in a plane normal thereto, a wire bending tool on said holder and spaced radially from said axis, means on said holder for driving wire into said tool during rotation of said holder about said axis, and driving means for rotating said unit about said axis, said tool including means for producing an S-curve in the wire during passage therethrough, the first turn of the S being away from said axis and the second turn about a center near said axis, said tool being formed to provide a short slot for the wire extending along an axis substantially tangential to the path of rotation thereof and having a width slightly greater than the diameter of the wire to be used therewith.

2. An apparatus for the continuous production of helically coiled spring wire or the like which comprises a unit mounted for rotation about a fixed axis, said unit comprising a tool holder mounted for rotation about said axis in a plane normal thereto, a wire bending tool on said holder and spaced radially from said axis, means on said holder for driving wire into said tool during rotation of said holder about said axis, and driving means for rotating said unit about said axis, said tool including means for producing an S-curve in the wire during passage therethrough, the first turn of the S being away from said axis and the second turn about a center near said axis, said wire driving means is connected to be driven by said means for rotating said unit.

3. An apparatus for the continuous production of helically coiled spring wire or the like which comprises a unit mounted for rotation about a fixed axis, for said unit comprising a tool holder mounted for rotation about said axis in a plane normal thereto, a wire bending tool on said holder and spaced radially from said axis, means on said holder for driving wire into said tool during rotation of said holder about said axis, and driving means for rotating said unit about said axis, said tool including means for producing an S-curve in the wire during passage therethrough, the first turn of the S being away from said axis and the second turn about a center near said axis, said wire driving means and said unit driving means being connected by a planetary gearing including a fixed sun gear and a planet gear and said planet gear being driven around said sun gear with rotation of said unit and said wire driving means being connected to be driven by said planet gear.

4. An apparatus for the continuous production of helically coiled spring wire or the like as set forth in claim 1 including a guide deflector mounted on said unit and spaced from said slot on the side thereof toward said wire driving means for producing an initial bend of the wire away from said axis.

5. An apparatus for the continuous production of helically coiled spring wire or the like which comprises a unit mounted for rotation about a fixed axis, said unit comprising a tool holder mounted for rotation about said axis in a plane normal thereto, a wire bending tool on said holder and spaced radially from said axis, means on said holder for driving wire into said tool during rotation of said holder about said axis, and driving means for rotating said unit about said axis, said tool including means for producing an S-curve in the wire during passage therethrough, the first turn of the S being away from said axis and the second turn about a center near said axis, said tool comprising three guide deflectors spaced from one another tangentially of the path of rotation and the outer two of said deflectors being spaced radially farther from said axis of rotation than the intermediate one of said deflectors.

6. The apparatus of claim including means for adjusting the positions of said guide deflectors with respect to one another and with respect to said axis of rotation.

7. An apparatus for forming a helical coil of spring wire or the like about a predetermined axis comprising a rigid shoulder, means for holding said shoulder facing radially outwardly of said axis at a position spaced radially from said axis and closely adjacent the outer circumference of the coil to be formed, means for guiding a wire to be coiled through a plane transverse to said axis and over said shoulder, means for moving the wire continuously through said guiding means and over said shoulder and for pressing the wire against said shoulder with a force sufficient to deform the wire plastically at said shoulder whereby the wire leaves the shoulder in a curve extending radially outwardly from said shoulder in said plane and about an axis substantially parallel to said predetermined axis, and means for engaging the wire after its passage over said shoulder for urging it toward said predetermined axis and for bringing the axis of curvature of the wire into coincidence with said predetermined axis.

8. The apparatus of claim 7 including means for adjusting the position of said shoulder with respect to said guiding means and for changing the position about said axis of the line between said guiding means and said shoulder.

9. The apparatus of claim 7 wherein said engaging means comprises a cylindrical body mounted with its axis coinciding with said predetermined axis for relative movement along said predetermined axis with respect to said guiding means and wherein said curved wire is guided about said body and into wrapping engagement with the surface thereof.

10. The apparatus of claim 7 wherein said wire engaging means comprises a wire bending deflector spaced from said shoulder for pressing engagement with the outer side of the wire whereby the wire first passes through said guiding means and over said shoulder and is then engaged and bent to bring the axis of its curvature into substantial coincidence with said predetermined axis.

11. The apparatus of claim 10 including means for adjusting the position of said shoulder and said bending deflector with respect to one another and with respect to said axis.

12. An apparatus for the continuous production of helically coiled spring wire or the like which comprises a rigid base, a hollow cylindrical support rigidly attached to said base, a drive shaft mounted within said support and extending beyond one end thereof, a tool holder mounted on said one end and rigidly secured thereto, a wire forming tool on said holder, power means on said holder for driving a wire into engagement with said tool for forming the wire in a helical coil, means for rotating said shaft, and gearing means connecting said shaft and said power means for actuating said power means whereby said wire is concurrently driven into engagement with said tool and is rotated about the axis of said support, the

rate of rotation of said shaft and the driving rate of said wire being coordinated to maintain the finished coil substantially stationary without rotation about the axis of said shaft.

13. An apparatus for the continuous production of helically coiled spring wire or the like as set forth in claim 12 including a wire supply spool mounted on the outside of said support for free rotation with respect thereto, and means for feeding wire from said spool into said power means.

14. An apparatus for the continuous production of helically coiled spring wire or the like as set forth'in claim 12 wherein said shaft is hollow and including bearing means within said shaft for mounting a tube for free rotation within said shaft and for free axial movement therethrough, said bearing means positioning said tube concentrically with respect to the axis of said shaft.

15. The method of producing a helical coil of spring wire or the like which comprises providing a shoulder of rigid material, holding a length of wire to be formed transversely of the shoulder and while moving the wire and shoulder lengthwise of the wire with respect to one another urging the wire against the shoulder with sufficient force to plastically deform the wire at the shoulder such that on leaving the shoulder the wire bends abruptly away from the shoulder and forms in a curve about an axis spaced from the shoulder on the side of the shoulder remote from the side of the shoulder in engagement with the wire, and guiding the curved wire into a coil having its axis substantially parallel to that of the curve of the wire and its outer circumference closely adjacent to the shoulder.

16. The method of claim 15 wherein the shoulder is of relatively small radius of curvature as compared with the diameter of the helical coil to be formed and the wire is moved over the shoulder in frictional engagement therewith.

17. The method of claim 15 including the steps of providing a second shoulder and a wire engaging element for the guiding of the curved wire and holding the second shoulder ahead of the first shoulder on the opposite side of the wire and wherein the urging of the wire against the first shoulder is effected by locating the second shoulder and the guiding element in positions on respective opposite sides of the first shoulder along the wire and engaging the wire on the side of the wire opposite the side engaged by the first shoulder.

18. The method of claim 17 including the step of adjusting the pressure between the wire and the first shoulder by changing the angular position of the line from the first shoulder to the second shoulder.

19. The method of claim 15 including the steps of rotating said shoulder continuously about the axis of the coil and moving the wire over said shoulder at a rate to prevent rotation of the coil being formed.

20. The method of wrapping a helical coil of spring wire or the like about a cylindrical body in engagement therewith which comprises providing a cylindrical body, providing a shoulder of rigid material and positioning it closely adjacent the outer surface of the body in alinement with the longitudinal axis of the body and facing away from the body, passing the wire over the shoulder transversely of the longitudinal axis of the body and onto the body and while rotating the body and shoulder with respect to one another urging the wire against the face of the shoulder with sufiicient force to plastically deform the wire at the shoulder whereby on leaving the shoulder the wire bends in a curve opening toward the body and extending radially outwardly beyond the shoulder and back toward the body, wrapping the wire about the body during the relative rotation thereof with respect to the shoulder, and moving the body axially with respect to the shoulder to form a helical coil.

21. The method of claim 20 including the initial step of providing a smooth, uniform coating of plastic mate- 13 rial on the wire and wherein the material of the surface of the body is plastic having physical characteristics essentially the same as those of the coating on the wire.

22. The method of claim 20 including the step of preventing rotation of the body while rotating the shoulder at a uniform rate about the body and maintaining the supply of the wire at a rate just suflicient to wrap the wire about the body whereby the body moves forward axially with the coil in engagement therewith and without rotation.

23. The method of forming a helical coil of spring wire or the like about a cylindrical form as set forth in claim 20 including the step of effecting axial movement of the tube at a rate to form the adjacent turns of the helical coil in engagement with one another.

References Cited UNITED STATES PATENTS 6/1913 Byrnes 29-173 Sleeper 72-66 Ekstedt 72-135 Owston 72-66 Pierce 7'2-135 Kirchner 72-135 Giros 72-135 Jaycox 72-66 Chenex et al.

Montignot 72-135 Heckethom et al.

FOREIGN PATENTS Great Britain.

15 CHARLIE T. MOON, Primary Examiner US. Cl. X.R.