GB2343857A

GB2343857A - Spring manufacture

Info

Publication number: GB2343857A
Application number: GB9924552A
Authority: GB
Inventors: Donal Thomas Curry; Donald Anthony Curry
Original assignee: BRAY PRECISION TOOLING Co
Current assignee: BRAY PRECISION TOOLING Co
Priority date: 1998-11-20
Filing date: 1999-10-19
Publication date: 2000-05-24
Also published as: GB9924552D0

Abstract

A spring coiling apparatus made up of a spring coiling machine and a wire feeding device in which the spring coiling machine comprises means for coiling the wire into a spring, the coiling means defining coiling points for receiving the wire and a mandrel 65 for cutting the spring from the wire characterised in that the coiling points e.g. 76 are adapted to minimise contact with the wire and a wire feeding device for feeding wire to the spring coiling machine.

Description

"Spring manufacture" This invention relates to spring manufacture and in particular to a spring coiling apparatus made up of a spring coiling machine and a wire feeding device and to a method of manufacturing a spring.

Springs are usually manufactured using complex apparatus. Typically, a spring is manufactured from a continuous wire which is fed from a swift into a spring coiling machine which is calibrated to produce a spring of the desired spring index, pitch and length. The spring index is defined as the diameter of the spring, D, divided by the diameter, d, of the wire from which the spring is formed.

In general, most springs have a spring index ranging from three to twelve. However, springs for some specialised applications must have spring indices greatly outside the three to twelve range. Examples of springs requiring a high spring index are springs employed in tracheal tubes. Tracheal tubes are formed from a spring encased in a plastics material to impart resilience to the tube to facilitate intubation of a patient during medical procedures.

Springs having a spring index outside the three to twelve range are in general difficult to manufacture. For example, springs having a spring index greater than twelve are unstable as they tend to become floppy and lose their shape. Typical tracheal springs have a spring index of between twenty-five to thirty-eight and accordingly due to their instability are extremely difficult to manufacture in a reproducible and reliable way.

In the manufacture of springs, a considerable length of wire can be required to manufacture the spring depending upon the nature and length of the spring. Accordingly, in the manufacture of comparatively long springs such as the tracheal tubes which can be formed from between about 5 and 12 metres of wire, the wire must be fed from the swift into the apparatus for coiling into a spring. A continuous and uninterrupted feed is required in order to avoid variations in spring pitch and the like which can result in a finished product which fails to meet the desired specification. However, known apparatus for feeding wire into spring coiling machines can suffer from interrupted or jerky feeding of wire from the swift thereby increasing the failure rate of the finished product.

The nature of the wire material used in the manufacture of springs can also determine or restrict the method and apparatus which can be employed for the manufacture of the spring. For example, in the manufacture of tracheal springs, a tin-coated music wire is generally used due to its tensile strength, hygienic nature of the tin coating and the pleasing aesthetic effect of the wire. However, the wire may be easily stripped of the tin coating during manufacture which results in unacceptable rejection rates in the finished product.

An object of the invention is to overcome the problems of the prior art.

A further object of the invention is to provide an improved spring manufacturing apparatus.

A still further object of the invention is to provide an improved method of spring manufacture.

Yet a further object of the invention is to provide an apparatus and method of tracheal spring manufacture.

According to the invention there is provided a spring coiling machine comprising means for drawing wire into the machine, coiling means for coiling the wire into a spring, the coiling means defining coiling points for receiving the wire and a mandrel for cutting the spring from the wire characterised in that the coiling points are adapted to minimise contact with the wire.

Preferably, the coiling points are adapted to contact the wire at a single point to minimise contact with the wire. More preferably, the coiling points are dimensioned to have a diameter greater than the diameter of the wire.

Suitably, the mandrel defines a coiling point.

Preferably, the coiling means comprises two coiling fingers and the coiling point defined by the mandrel is located between the mandrel and a coiling finger.

Advantageously, the machine further comprises guide means for guiding wire from the means for drawing wire into the machine to the coiling means. Suitably, the guide means comprises an extension to support the wire adjacent to the coiling means.

Preferably, the means for drawing the wire into the machine comprises two rollers for gripping the wire therebetween to draw the wire into the machine.

Advantageously, the spring coiling machine further comprises external guide means for guiding wire to the means for drawing wire into the machine. Suitably, the spring coiling machine further comprises cutting means co-operable with the mandrel for cutting the spring from the wire. Preferably, the spring coiling machine further comprises straightening means for straightening the wire prior to drawing the wire into the machine.

The invention also extends to a wire feeding device for feeding wire to a spring coiling machine from a swift comprising pulley means for receiving wire from the swift, a path defined by the pulley means to convey the wire to the spring coiling machine, a wire take-up defined by the path for forming into a spring in the spring coiling machine and drive means for rotating the swift to discharge the wire from the swift to the pulleys to form the wire take-up.

Preferably, the pulleys comprise springs through which the wire is threaded. More preferably, a plurality of pulleys define the path.

Advantageously, the pulleys are mounted on arms.

Suitably, at least one arm is moveable between a wire feeding position to feed the wire take-up to the spring coiling machine and a resting position to support the wire in the path. Suitably, the at least one arm is moveable on a pivoting means.

The invention also extends to an apparatus comprising a spring coiling machine as hereinbefore defined.

In a preferred embodiment of the invention, the apparatus further comprises a wire feeding device as hereinbefore defined.

The invention also extends to a method of coiling a wire comprising drawing the wire into a spring coiling machine coiling the wire at coiling points within the machine and cutting the coiled spring from the wire at a mandrel characterised in that contact of the wire with the coiling points is minimised.

Suitably, the coiling points are dimensioned to loosely accommodate the wire such that the wire is contacted with the coiling points at a single point only.

Preferably, the method further comprises the step of coiling on the mandrel.

Advantageously, the method further comprises the step of guiding the wire to the coiling means.

Suitably, the method comprises the step of straightening the wire prior to coiling. Advantageously, the method comprises the step of loosely suspending the wire in a feeding device before straightening the wire to facilitate un-interrupted take-up of the wire prior to coiling.

Various embodiments of the invention will now be described by way of example only having regard to the accompanying drawings, in which: Fig. 1 is a partially schematic front perspective view from above and one side of a spring coiling apparatus made up of a spring coiling machine and a wire feeding device, with an operator seated at the spring coiling apparatus, in accordance with the invention; Fig. 2 is a top plan view of the spring coiling apparatus of Fig. 1; Fig. 3 is an enlarged front elevation of the tooling arrangemen of the spring coiling machine of the spring coiling apparatus; Fig. 4 is a side elevation of a spring showing the spring diameter, the wire diameter and the length of the spring; Fig. 5 is an enlarged cross-sectional view through a coiling finger of a tooling arrangement of the prior art with a wire for forming into a spring positioned within the coiling point of the coiling finger, and Fig. 6 is an enlarged cross-sectional view through the coiling finger of the tooling arrangement of Fig. 3 with a wire for forming into a spring positioned in the coiling point of the coiling finger.

As shown in the drawings, a spring coiling apparatus in accordance with the present invention is generally indicated by the reference numeral 1 and is made up of a spring coiling machine 2 and a wire feeding device 3 for feeding wire to the spring coiling machine 2 from a renewable wire bearing swift 6 mounted within the wire feeding device 3. An operator 4 operates the spring coiling machine 2 to manufacture springs 45 from the wire fed from the feeding device 3 which are in turn supported in a collection cage 5 following manufacture as shall be explained more fully below.

The wire swift 6 is formed from a double-walled type cylinder and is mounted on an upright shaft 8 along its central longitudinal axis. The swift 6 is annular and is provided with an opening 11 defined by an inner wall 80 of the swift 6 for receiving the shaft 8. Transversely disposed supporting spokes 10 extend between the inner wall 80 and the outer wall 81 of the swift 6. Wire 9 for forming into a spring 45 is wrapped about the outer wall 81 of the swift 6 for discharging into the spring coiling machine 2 as shall be explained more fully below. The wire swift 6 is adapted to rotate on the shaft 8 and externally is further supported in a holding wheel 7 which extends laterally outwards from the swift 6 and is disposed substantially transversely to the longitudinal axis of the shaft 8.

The shaft 8 is rotatable by a motor 12 disposed beneath the holding wheel 7 and mounted on the shaft 8. The motor 12 is contained within a box-like motor housing 32 supported on a stand 13 having a flat circular base 14 and an upright 15 extending upwards therefrom on which the motor 12 and motor housing 32 are mounted.

The wire 9 from the swift 6 is threaded in an anti-clockwise direction when viewed from above as shown in Fig. 2 to a first spring-like pulley 16 located adjacent the swift 6. The first pulley 16 is mounted at the free end of a first pulley arm 28 which is in turn mounted at its opposite end 29 on the motor housing 32. The arm 28 is supported on a lug 30 located on the motor housing 32 and is secured to the lug 30 by a bolt 31.

The first pulley 16 is formed from an elongate mounting spring 17 attached to the arm 28 and an elongate receiving spring 18 disposed at the free end of the mounting spring 17 and disposed transverse to the mounting spring 17 through which the wire 9 is threaded.

The wire 9 is in turn fed from the first pulley 16 in an anticlockwise direction when viewed from above as shown in Fig. 2 to a second spring-like pulley 19 similar to the first spring-like pulley 16. The second pulley 19 is mounted on a telescopic portion 22 of a pole 20 so that the location of the second pulley 19 may be varied as required. The pole 20 is mounted on a pole base 21 in a vertically upright disposition.

The wire 9 is threaded through the transverse wire receiving portion 18 of the second pulley 19 in an anti-clockwise direction to a third spring-like pulley 23 disposed opposite the first spring-like pulley 16 along an anti-clockwise path with the swift 6 located between the first pulley 16 and the third pulley 23. The third pulley 23 is supported on a third pulley supporting arm 24 having one end 25 thereof mounted on a lug 26 located on the motor housing 32. The third pulley supporting arm 24 is secured to the lug 26 by a bolt 27.

The third pulley 23 is provided with a transverse wire receiving portion 18 only through which the wire 9 is threaded.

The wire 9 is in turn threaded in an anti-clockwise direction from the third pulley 23 to a fourth spring-like pulley 33 through which the wire 9 is passed and in turn fed to the spring coiling machine 2 of the spring coiling apparatus 1.

The fourth pulley 33 is similar in construction to the first pulley 16 and is supported on a fourth pulley arm 34. The fourth pulley arm 34 is in turn mounted on a support bracket 35 which is supported on a primary mounting arm 36 attached at its end remote from the support bracket 35 to the motor housing 32. The support bracket 35 is provided with a pivot mounting 37 for receiving the fourth pulley arm 34 so that the fourth pulley arm 34 is pivotably mounted in the pivot mounting 37. The fourth pulley arm 34 is also supported in a reinforcing arm support clamp 38 contiguous with the arm 34 and pivotable about the pivot mounting 37.

The support clamp 38 is attached to a biased spring 39 which is in turn fixed to a spring fixing point 40 on the support bracket 35 so that the arm 34 is pivotable between a forward position i. e. anticlockwise towards the spring coiling machine 2 and a resting or back position oriented in a clockwise disposition with respect to the spring coiling machine 2. The fourth pulley arm 34 is returned to a rest position by the biased spring 39 following a pivoting movement in the pivot mounting 37.

The spring-like pulleys 16,18,23 and 33 facilitate movement of the wire 9 from the swift 6 through the wire feeding device 3 in an uninterrupted and jerk-free manner due to the flexible floppy nature of the pulleys 16, 18,23 and 33. In addition, the arms 28,24 and 34 and the pole 20 facilitate suspension of the wire between the pulleys 16, 18, 23 and 33 in a substantially relaxed, loose and friction free manner so that sufficient wire is always threaded through the feeding device 3 to satisfy the take-up demand of the spring coiling machine 2 during spring formation without resulting in jerking or interruption of wire feeding and without requiring passage of the wire 9 through wheel-type pulleys and the like which can cause stripping of the wire 9 prior to coiling in the coiling machine 2.

The spring-like nature of the pulleys 16,18,23 and 33 minimises resistance during feeding of the wire thereby further reducing interruptions in wire feeding. The pivotable nature of the fourth spring like pulley arm 34 also ensures a smooth flow of wire 9 to the spring coiling machine 2 in an uninterrupted fashion.

The wire 9 is fed from the fourth pulley 33 to a spring coiling tooling arrangement 41 of the spring coiling machine 2 via a wire straightening tooling arrangement 79 on the machine 2.

Fig. 3 shows an enlarged front elevation of a tooling arrangement of the spring coiling machine for the manufacture of springs in accordance with the present invention. The tooling arrangement of the invention can be adapted for use in a multiplicity of spring coiling machine types and apparatus as will be appreciated by those skilled in the art.

An example of a preferred machine suitable for use in the apparatus of the invention is the universal spring coiling machine, model UFM-8 available from Wafios Maschinenfabrik GmbH & Co. Kommanditgesellschaft of Reutlingen. A description of the machine is to be found in the operating instructions for the spring coiling machine the contents of which are incorporated herein by reference.

As shown in Fig. 3 the tooling arrangement of the spring coiling machine 2 is made up of a top feed roller 46 and a bottom feed roller 47 disposed below the top feed roller 46 between which the wire 9 is received from the wire straightening tooling arrangement 79. The top feed roller 46 and the bottom feed roller 47 grip and draw the wire 9 into the spring coiling machine 2 from the wire straightening tooling arrangement 79 and the wire feeding device 3. The top feed roller 46 is provided with a centrally located top opening 50 for rotatably mounting the top feed roller 46 on a top shaft 48 while the bottom feed roller 47 is also provided with a centrally located opening 51 for mounting the bottom feed roller 47 on a bottom shaft 49 on which the bottom feed roller 47 can rotate.

The top feed roller 46 is secured to the top shaft 48 by a top mounting ring 52 while the bottom feed roller 47 is secured to the bottom shaft 49 by a bottom mounting ring 53. The top and bottom feed rollers 46,47 in combination draw the wire 9 into the tooling arrangement of the spring coiling machine 2.

The direction of rotation of the top and bottom feed rollers 46, 47 respectively is indicated by the arrows in Fig. 3.

An external wire guide 54 for guiding wire 9 between the top and bottom rollers 46, 47 is located adjacent the top and bottom rollers 46, 47. The external wire guide 54 is made up of an external wire guide elongate body portion 56 which substantially surrounds the wire 9 and guides the wire 9 between the top and bottom rollers 46,47 and an external wire guide tapered body portion 57 contiguous with the elongate body portion 56. The tapered body portion 57 of the external wire guide 54 is shaped and contoured to nestle between the top and bottom feed rollers 46,47 but stops short of the wire gripping faces of the top and bottom feed rollers 46,47.

The tooling arrangement is also provided with an internal wire guide 55 adapted to guide the wire 9 from the top feed roller 46 and bottom feed roller 47 to first and second coiling fingers 66,67. The internal wire guide 55 is broadly similar to the external wire guide 54 and is provided with an internal wire guide elongate body portion 58. However, the internal wire guide elongate body portion 58 is located between a first tapered portion 59 at one end of the internal wire guide elongate body portion 58 and adapted to nestle between the top feed roller 46 and bottom feed roller 47 and a second tapered portion 60 at the end remote from the first tapered portion 59 for guiding the wire 9 to the first and second coiling fingers 66,67.

The second tapered portion 60 is provided with a guide extension 82 to terminate immediately adjacent a cutting mandrel 65 located between the first coiling finger 66 and the second coiling finger 67. In the present invention the cutting mandrel 65 also serves as a coiling point 83 for the wire 9 as shall be explained more fully below. The mandrel 65 is semi-circular in shape when viewed in plan as shown in Fig. 3 and has a curved face 86 orientated to face towards the first and second coiling fingers 66,67 and a flat face 87 disposed towards the first pitching tool 63. The third coiling point 83 is defined on the curved face 86 of the mandrel 65 between the flat face 87 of the mandrel 65 and the coiling point 76 of the first coiling finger 66.

The mandrel 65, is adjustable as required to vary the diameter of the spring 45 as shall be explained more fully below.

The guide extension 82 of the second tapered portion 60 of the internal wire guide 54 ensures a reproducible coiling of wire without interruption and the coiling of wire having high spring indices due to the additional support provided by the guide extension 82.

The second tapered portion 60 of the internal wire guide 55 is located between a pitch tool 61 to define the pitch of the spring 45 formed from the wire 9 and a cutting blade 62 adapted to co-operate with the mandrel 65 to cut a finished spring 45 from the wire 9. A first pitch tool 63 adapted to be located parallel to the spring 45 axis is disposed adjacent the second extended tapered portion 60 of the internal wire guide 55 while a second pitch tool 64 is disposed parallel to the spring axis on the opposite side of the second extended tapered portion 60 of the internal wire guide 55.

The pitch tools 63, 64 serve to control the pitch of a finished spring 45. The pitch tools 63,64 are adjusted so that the spring produced employing the spring coiling machine in accordance with the invention can be a closed coiled spring i. e. with no gaps between the coils of the spring 45 or a pitch spring in which gaps are present between the coils 45.

The tooling arrangement of Fig. 3 is further provided with two camping pins 68 for securing the first and second coiling fingers 66, 67 in position.

The tooling arrangement of Fig. 3 is further provided with knurled screws 69 and 73 for adjusting the coiling points on a first or Z axis of the tool 45 while the tooling arrangement is also provided with a knurled screw 64 for adjusting the coiling points of the spring 45 along an X-Y axis as will be appreciated by those skilled in the art.

The coiling points are supported and held in position by a pin holder 70, a bearing 71 and a second pin holder 72 in the tooling arrangement.

The first and second coiling fingers 66, 67 of the tooling arrangement project outwards from respective mounting blocks 84, 85 towards the mandrel 65. At their free ends, the first and second coiling fingers are provided with groove-like coiling points 76. The groove-like coiling points 76 are adapted to receive the wire 9 from the guide extension 82 of the internal wire guide 55. More particularly, the wire 9 is first received within the groove-like coiling point 76 of the second coiling finger 67 and guided by the coiling point 76 of the second coiling finger 67 to the groove-like coiling point 76 of the first coiling finger 66 along an arcuate path as shown in Fig. 3. In addition to the two coiling points 76 defined by the first and second coiling fingers 66, 67, the wire is further supported at the third coiling point 83 defined by the mandrel 65. Fig. 5 shows a crosssectional view through a coiling finger 66, 67 of the prior art provided with a groove-like coiling point 75. As shown in the drawing, the coiling point 75 is shaped to be semi-circular in shape when viewed in cross-section and is dimensioned to enjoy a comparatively tight fit with the wire 9 so that maximum contact of the coiling point 75 is maintained with the wire 9 at the contacting face 77 of the coiling point 75. The coiling point 75 is so dimensioned and shaped in accordance with the prior art to maximise control and support of the wire 9 during coiling. In contradistinction, Fig. 6 shows a cross-sectional view through the coiling fingers 66,67 of the tooling arrangement of the present invention in which the coiling point 76 is shaped and dimensioned to enjoy a loose fitting contact with the wire 9. More particularly, the wire 9 is in contact with the coiling point 76 at a comparatively small single contact point generally indicated by the reference numeral 78. The coiling point 76 therefore provides support and guidance to the wire 9 whilst minimising contact with the wire 9 to prevent stripping of tin-like coatings and the like from the wire 9. As shown in Fig. 6, the diameter of the wire 9 is generally indicated by the designation"d" while the transverse width of the coiling point 76 is indicated by the designation"X". Accordingly, in accordance with the present invention, X is greater than d to minimise contact of the wire 9 with the coiling point 76.

Generally, it has been found that satisfactory results are achieved where X is 0.004 inches greater than d e. g. if d = 0. 010, X is 0.014.

The third coiling point 83 further defines the arcuate path of the wire 9, and serves to enhance support and control of the wire 9 during coiling.

The third coiling point 83, in particular, compensates for the relatively large dimensions of the coiling points 76 of the first and second coiling finger 66, 67. The coiling points 76 are dimensioned so that the wire 9 enjoys a comparatively loose fit within the coiling points 76.

The provision of the third coiling point 83 compensates for the reduced support provided to the wire 9 by the minimised contact point 78 of the coiling points 76 of the invention. The arrangement of the three coiling points 76 and 83 of the invention therefore maximises control but minimises contact of the wire 9 with potentially stripping surfaces. The mandrel 65 of the tooling arrangement therefore serves as the third coiling point to securely hold the wire 9 between the coiling point 83 of the mandrel 65 and the coiling point 76 of the first coiling finger 66.

In use, the spring coiling apparatus of the invention is assembled as previously described with the wire feeding device 3, and the spring coiling machine 2 arranged substantially as shown in Figs. 1 and 2.

The spring coiling machine 2 and the wire feeding device 3 are actuated by the operator 4 in a manner familiar to those skilled in the art. The tooling arrangement of the spring coiling machine 2 is arranged as shown in Fig. 3. Accordingly, upon actuation of the spring coiling machine 2 and the wire feeding device 3, wire is drawn from the swift 6 through the wire feeding device 3 as previously described, to the wire straightening tooling arrangement 79, through the external wire guide 54 and between the top feed roller 46 and bottom feed roller 47 of the tooling arrangement shown in Fig. 3. The wire 9 is then directed by the internal wire guide 54 via the guide extension 82 to the coiling points 76 and 83 defined by the first and second coiling fingers 66, 67 and the mandrel 65. The coiling points 76 and 83 cause the wire 9 to be coiled into a spring 45 which is then cut from the wire 9 by the operator 4 upon actuation of the cutting blade 62 which is urged inwards towards the mandrel 65 to cut the finished spring 45 from the wire 9. As will be appreciated by those skilled in the art, the tooling arrangement of Fig. 3 is adjusted and calibrated to produce a spring 45 having the desired pitch, length and spring index. As shown in Fig. 4, the spring 45 is formed from a wire 9 having a diameter d, a length L and a spring diameter indicated by the letter D while the spring index can be calculated from d and D.

For example, where a wire 9 having a diameter, d, of 0.010 inches is employed to manufacture a spring 45 having a spring index greater than 12, the coiling points 76,83 are calibrated to range between 0.002 inches to 0.004 inches above the diameter, D of the wire 9.

Accordingly, in the present example, the coiling points 76,83 have a diameter of approximately 0.012 to 0.014 inches. The diameter, D, of the spring 45 is also determined by the location of the mandrel 65 within the tooling arrangement so that adjustment of the location of the relative position of mandrel 65 in the tooling arrangement can be used to vary the diameter, D, of the spring 45.

It has been estimated that due to the provision of"loose"coiling points 76 and 83 in accordance with the present invention, spring reject rates can be reduced to a rate of below 3% as compared with tooling arrangements in the apparatus of the prior art in which contact between the wire 9 and the coiling points is maximised.

The applicants have also found that stripping of coated wire 9 for coiling is further reduced where the tinned wire 9 is allowed to mature or cure for a period of three to four months prior to use.

Although the applicants do not wish to bound by any theorem, it is believed that the tin coating of the wire 9 enjoys a stronger bond with the wire following the maturation process. Maturation can be effected at room temperature for the aforementioned period of three to four months.

Following the manufacture of a spring 45 in the spring coiling machine 2, the spring is deposited by the operator 4 in the collection cage 5.

The collection cage 5 is made up of a cage like frame 42 having a floor 43 therein. Spring holding rods 44 extend upwards from the cage floor 43 for receiving and supporting springs 45 in an upright and straight fashion prior to parking and transportation.

The invention is not limited to the embodiments herein described which can be varied in construction and detail.

Claims

CLAIMS 1. A spring coiling machine comprising means for drawing wire into the machine, coiling means for coiling the wire into a spring, the coiling means defining coiling points for receiving the wire and a mandrel for cutting the spring from the wire characterised in that the coiling points are adapted to minimise contact with the wire.
2. A spring coiling machine as claimed in Claim 1 characterised in that the coiling points are adapted to contact the wire at a single point to minimise contact with the wire.
3. A spring coiling machine as claimed in Claim 1 or Claim 2 characterised in that the coiling points are dimensioned to have a diameter greater than the diameter of the wire.
4. A spring coiling machine as claimed in any of Claims 1 to 3 characterised in that the mandrel defines a coiling point.
5. A spring coiling machine as claimed in Claim 4 characterised in that the coiling means comprises two coiling fingers and the coiling point defined by the mandrel is located between the mandrel and a coiling finger.
6. A spring coiling machine as claimed in any of Claims 1 to 5 further comprising guide means for guiding wire from the means for drawing wire into the machine to the coiling means.
7. A spring coiling machine as claimed in Claim 6 characterised in that the guide means comprises an extension to support the wire adjacent to the coiling means.
8. A spring coiling machine as claimed in any of Claims 1 to 7 characterised in that the means for drawing the wire into the machine comprises two rollers for gripping the wire therebetween to draw the wire into the machine.
9. A spring coiling machine as claimed in Claim 8 further comprising external guide means for guiding wire to the means for drawing wire into the machine.
10. A spring coiling machine as claimed in any of Claims 1 to 9 further comprising cutting means co-operable with the mandrel for cutting the spring from the wire.
11. A spring coiling machine as claimed in any of Claims 1 to 10 further comprising straightening means for straightening the wire prior to drawing the wire into the machine.
12. A wire feeding device for feeding wire to a spring coiling machine from a swift comprising pulley means for receiving wire from the swift, a path defined by the pulley means to convey the wire to the spring coiling machine, a wire take-up defined by the path for forming into a spring in the spring coiling machine and drive means for rotating the swift to discharge the wire from the swift to the pulleys to form the wire take-up.
13. A wire feeding device as claimed in Claim 12 characterised in that the pulleys comprise springs through which the wire is threaded.
14. A wire feeding device as claimed in Claim 12 or Claim 13 characterised in that a plurality of pulleys define the path.
15. A wire feeding device as claimed in any of Claims 12 to 14 characterised in that the pulleys are mounted on arms.
16. A wire feeding device as claimed in Claim 15 characterised in that at least one arm is moveable between a wire feeding position to feed the wire take-up to the spring coiling machine and a resting position to support the wire in the path.
17. A wire feeding device as claimed in Claim 16 characterised in that the at least one arm is moveable on a pivoting means.
18. A spring coiling apparatus comprising a spring coiling machine as claimed in any of Claims 1 to 11.
19. Apparatus as claimed in Claim 18 further comprising a wire feeding device as claimed in any of Claims 12 to 17.
20. A method of coiling a wire comprising drawing the wire into a spring coiling machine, coiling the wire at coiling points within the machine and cutting the coiled spring from the wire at a mandrel characterised in that contact of the wire with the coiling points is minimised.
21. A method as claimed in Claim 20 characterised in that the coiling points are dimensioned to loosely accommodate the wire such that the wire is contacted with the coiling points at a single point only.
22. A method as claimed in Claim 20 or Claim 21 characterised in that the wire is coiled on the mandrel.
23. A method as claimed in any of Claims 20 to 22 further comprising the step of guiding the wire to the coiling means.
24. A method as claimed in any of Claims 20 to 23 further comprising the step of straightening the wire prior to coiling.
25. A method as claimed in any of Claims 20 to 24 further comprising the step of loosely suspending the wire in a feeding device before straightening the wire to facilitate un-interrupted take-up of the wire prior to coiling.