AU5847696A

AU5847696A - Spring formation

Info

Publication number: AU5847696A
Application number: AU58476/96A
Authority: AU
Inventors: Stuart Hamil; Lynn Craig Turner
Original assignee: Sleepyhead Manufacturing Co Ltd
Current assignee: SLEEPYHEAD MANUFACTURING Co Ltd
Priority date: 1995-05-26
Filing date: 1996-05-27
Publication date: 1996-12-11
Also published as: ZA964251B; WO1996037320A1

Description

SPRING FORMATION

BACKGROUND TO THE INVENTION

1. FIELD OF THE INVENTION

This invention relates to spring formation and more particularly to methods and apparatus for spring formation and a spring so formed.

2. DESCRIPTION OF THE PRIOR ART

In mattress manufacture, particularly inner-spring style mattress configurations there has been difficulties in certain bed constructions in maintaining the resilience of mattress springing throughout the life of the remainder of the mattress and furthermore, in controlling the positional relationship of the springs relative to remaining portions of the mattress.

In particular, the mattress manufacturing industry has known that a problem exists in controlling specifically the position of inner-springs within a mattress relative to ticking. In reality, there is a significant potential problem in reducing the likelihood of a spring, during the course of the life of the mattress, projecting through the padding and ticking of the mattress in the course of use. Various attempts in the past have been made to reduce the likelihood of unwanted spring penetration including securing, for example by clips and the like adjacent springs one with the other to arrange a spring armature for a mattress in a single unit, however, this has the disadvantage of reducing the extent to which springs can operate or compress independently one relative to the other, thus also potentially reducing the level of independent support which can be provided by each spring. It is, of course, appreciated that the springs are not only deflected by a load being directly encountered there above but also in sympathy with the deflection of adjacent springs to which they are clipped.

Other alternative spring armature arrangements have included the encapsulation of springs in foam plastic, or the adhering of portions of the springs with remaining portions of the mattress, these also, to some extent, present similar problems.

Commonly with the foregoing methods, there is almost inevitably associated therewith, complication with manufacture, cost (both labour and materials) and a potential for breakdown of the systems adopted.

Referring particularly to those constructions known as "pocket spring" mattress spring arrangements, there is often experienced in prior art units a special difficulty in controlling the potential unwanted penetration of springs in that each spring is pocketed substantially separately from other springs.

Use of adhesives association within the pockets have been made to control the movement of the springs relative to remaining portions of the bed, however, such an assembly is relatively complex in use, creates manufacturing plant difficulties in view of the inevitability of solvent evaporation, potential air pollution and worker safety difficulties. Furthermore, it is expected such systems are liable to breakdown in time.

As outlined above, coupled with the difficulty of control of prior art springing arrangements, there is also a need for manufacturing techniques to be readily included in a substantially automated manufacturing facility where continuous process can be achieved.

With prior art units and methods, the requirement for continuous processing, particularly with pocketed spring arrangements has resulted generally in untempered springs being used in mattresses. This step has the effect of reducing the useable life of the mattress over those with tempered springs, however, it has been found that owing to the need for tempering of the spring subsequent to completion of spring formation, there is often insufficient time to efficiently cool the spring prior to the spring being required for use in a spring pocket. Use of a hot spring often can lead to singeing, burning or melting of a fabric spring pocket within which it is engaged at the point of manufacture, leading to early breakdown of the mattress in use. The only other alternative is to slow the machinery down to allow time for springs to cool, however, this leads to inefficiency of manufacture and increased costs.

OBJECT OF THE INVENTION

It is an object of this invention to come some way to overcoming the abovementioned problems or least provide the public with a useful choice.

Other objects of this invention will become apparent from the following description and with reference to the preferred embodiment.

SUMMARY OF THE INVENTION

According to one aspect of this invention there is provided a method of forming a spring including positioning a partially formed compression spring in retaining means, bringing forming means into engagement with end portions of said spring deforming said end portions to orientate in a direction out of register with remaining portions of said spring and inclined inwardly of said spring toward a mid-portion thereof.

According to a further aspect of this invention there is provided a spring forming means including at least one guide means for engaging an end portion of said spring, forming means mounted with said guide means axially rotatable and longitudinally moveable to and from a position relative to the guide means to engage an end portion of said spring said forming means further moveable with said spring end portion engaged therewith to deform said spring to a predetermined configuration whilst adjacent spring portions are positioned by the guide means.

According to a further aspect of this invention there is provided a compression spring formed from a coil of elongate deformable material, at least one end portion of said spring being deformed out of annular register with remaining portions of said spring, orientated at least partially inwardly of said spring toward a mid portion thereof.

Other aspects of this invention should be considered in all its novel aspects will become apparent from the following description. - 6 -

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the drawings in which:

Figure l is a substantially diagrammatic cross- sectional side view of the spring formation apparatus according to the preferred embodiment of the invention, showing the formation of end portions of the spring with substantially simultaneous heat tempering of the spring prior to completion of formation of the spring;

Figure 2 is a substantially diagrammatic side view of the spring formed according to and by the apparatus of Figure 1; and

Figure 3 is a substantially perspective view from one side and above of an upper portion of the spring of Figure 2.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention will now be described with reference to the preferred form and in particular, a mattress spring armature spring for mattress manufacture according to "pocketed spring" technology. That is, where a plurality of separate wire compression springs are each engaged into a separate fabric pockets substantially separated from one another, but mounted substantially in position within mattress padding and ticking in accordance with substantially known technology.

Whilst the preferred form of the invention is described with reference to pocketed spring assemblies, the invention is not limited thereto and may be alternatively incorporated into other mattress and mattress spring configurations where appropriate.

In the preferred form of the invention, the spring in resilient wire material and preferably is substantially helically barrel shaped, that is having mid portion of a slightly wider diameter than end portions. The invention is, of course, not limited to this spring configuration. Preferably the spring is formed from elongate steel wire material of a type which is suitable for formation by bending and heat tempering, for example by controlled application of an electrical current between spaced apart portions thereof to heat the wire to predetermined temperature prior to controlled cooling.

Preferably the apparatus and method of the invention is provided upstream of a spring pocketing assembly to facilitate the manufacture of the spring for post- manufacture engagement on a feed conveyor for spring pocketing assemblies as part of a continuous process for spring manufacture, pocketing and mattress spring armature assembly.

Referring to the drawings, the spring of the invention is generally indicated by arrow 1 and is preferably formed in suitable mild steel wire material of a type which facilitates easy bending yet heat tempering to create substantially lasting stiffness in the resultant spring 1.

Preferably the spring 1 is arranged as a helical barrel compression spring having end portions 2 which are arranged into a termination coils to provide a pair of opposingly spaced apart substantially parallel planar load faces for the spring 1.

The end portions 2 in the preferred form of the invention are arranged, when completed, to terminate in a deformed portion 3 which is provided in the end portions of the wire from which the spring 1 is formed and which is bent, kinked or otherwise deformed out of the normal helical/annular register of the wire forming the spring 1, inclined inwardly of the spring 1 toward a mid portion thereof.

The effect of the above described inclination is such that the deformed portion 3 is orientated in a direction inwardly of the spring 1 from the substantially parallel planar spring end faces and where a tip 3a of the deformed portion 3 is actually faced inwardly of the spring 1 such that upon the spring 1 being compressed on a surface, the tip 3a tends to be directed and spaced away from such surface to resist penetration through said surface.

It will be appreciated that when so formed, the spring 1 can be relatively freely mounted within a mattress and adjacent the pocket fabric, padding and ticking. The effect of compression and any "rotation" of the spring relative to the pocket fabric, padding or ticking will not usually result in penetration of the tip 3a thereinto or, as hitherto has been the case, potential "threading" or "screwing" of a convential "undeformed" (in the sense described hereinbefore) spring 1 upon rotation through the padding or ticking, unless restrained.

It will thus be appreciated that by this invention the need for of adhesives, clipping and other assemblies normally used to maintain the positional relationships of the springs within the mattress and relative to padding and ticking is in most instances eliminated.

Referring now to Figure 1 the spring 1 is preferably formed through a spring coiling head (not shown) , which is so constructed as to convert a continuous wire supply fed through said coiling head into a partially formed helically barrel shaped compression spring. End portions 2 of the spring coil follow in substantially helical register with remaining portions of the wire element forming the spring coil.

When partially formed in this manner, the spring coil is preferably fed to the forming head as generally indicated by arrow 10 in figure 1 for spring completion and. tempering.

In the preferred form of the invention, the forming head 10 preferably includes a pair of spaced apart base portions 11 preferably formed in an electrically insulative material, for example phenolic reinforced fibrous material, plastics, ceramics and the like. Opposing operational faces 12 of the spaced apart base portions 11 preferably mount guide means 13 thereon, which are spaced apart a distance substantially commensurate with a diameter of the spring end portion 2 to define recesses 14 within which portions of the ends 2 of the spring coil can engage and be slid there along, for example by a pusher, conveyor finger or other assembly (not shown) .

It will thus be appreciated that the guide means 13 effectively restrains the spring coil top and bottom for subsequent operations. The spaced apart base portions 11 each include electrode means 15. In the preferred form, the electrode means 15 are connected with a controllable power supply and terminate on the opposing operational faces 12 thereof in strip conductors 16 so that portions of the spring coil end portions 2 impinge there against when engaged in the guides 13.

Clamping means 17 are preferably provided to one side of one of the guide means 13, each with a moveable finger member 18 actuable to provide a clamping of portions of said spring coil in said guide 13 to maintain the spring coil in position on the forming means 10, during formation of the deformed portions 3.

Deforming means 20 are preferably provided on each base portion 11. The deforming means 20 in the preferred form of the invention are each arranged as an elongate finger means 21, axially rotatable via a rotation arm 22 and longitudinally moveable via a control arm 23 so that elongate finger means 21 can each be bought into and out engagement with one end portion 2 of a spring coil engaged in the forming means, in a particular position. The finger means or clamping means 21 loosely hold the end portion of the spring and, upon rotation, deform the end of the spring. Although not shown, preferably suitable stop means are provided to control the axial orientation and position of the spring coil on the base portions 11 and held by the guide means 13. When so orientated and positioned, the clamping means 17 actuate to hold the spring coil in position and subsequently elongate finger means 21 moves inwardly, engages the portion 3 of the spring 1 end portion 2 within a slotted tip 25 thereof.

Axial rotation of the elongate finger means 21, will be seen to deform the end portion 3 of the spring out of helical register with the remaining portions of the spring coil and as hereinbefore described.

Preferably simultaneously with the deformation of the spring portion 3 as described hereinbefore, heat tempering of the spring coil is also undertaken, via a current passed through the spring coil between the electrodes 15. In this way, it will be appreciated that the spring 1 so formed and when cooled in a controlled manner can be substantially stress relieved or annealed and tempered.

Whilst the invention is described with reference to simultaneous deformation, annealing and tempering of the spring coil end portions 2, in alternative forms of the invention it is to be appreciated that annealing/tempering may be carried out prior to or subsequent to deformation of the spring end portions 2 whilst the spring coil is held in the guides 13.

The apparatus as described with reference to Figure 1 normally positioned upstream of a feeding mechanism for springs 1 to a mattress armature forming assembly. In this way, it will be appreciated that controlled cooling of the springs 1 after heat tempering can occur, either through exposure to ambient air or by virtue of enhanced cooling techniques.

It is the applicant's assertion that the deformation and tempering of the spring 1 at one station essentially within the spring manufacturing assembly phase enhances the opportunities for convenient formation, annealing/ tempering and controlled cooling of the spring, prior to subsequent operations, such as fabric pocketing, thus reducing the potential incidence of damage to the bed or mattress structure during manufacture and enabling faster controlled machine cycle times.

Thus by this invention there is provided an improved spring, spring manufacturing techniques and spring manufacturing method.

Claims

1. A method of forming a spring including positioning a partially formed compression spring in retaining means, bringing forming means into engagement with end portions of said spring deforming said end portions to orientate in a direction out of register with remaining portions of said spring and inclined inwardly of said spring toward a mid-portion thereof.

2. A method of forming a spring as claimed in claim

1 wherein the method incorporates the steps of tempering at least portions of said spring whilst positioned in the retaining means for deforming of said end portions.

3. A method of forming a spring as claimed in claim

1 or claim 2 wherein said spring comprises a substantially annularly helically wound coil spring.

4. A spring forming means including at least one guide means for engaging an end portion of said spring, forming means mounted with said guide means axially rotatable and longitudinally moveable to and from a position relative to the guide means to engage an end portion of said spring said forming means further movable with said spring end portion engaged therewith to deform said spring to a predetermined configuration whilst adjacent spring portions are positioned by the guide means.

5. A spring forming means as claimed in claim 4 including electrode means so positioned as to enable heating and/or tempering of said spring when positioned on said spring forming means.

6. A spring forming means as claimed in claim 4 wherein said forming means comprises an elongate finger means having an end portion adapted to engage said spring.

7. A compression spring formed from a coil of elongate deformable material, at least one end portion of said spring being deformed out of annular register with remaining portions of said spring, orientated at least partially inwardly of said spring toward a mid portion thereof.

8. A compression spring as claimed in claim 7 wherein said end portion is deformed inwardly in the direction of an axis of said spring.

9. A method of forming a spring substantially as hereinbefore described with reference to the accompanying drawings.

10. A spring forming means substantially as hereinbefore described with reference to the accompanying drawings.

11. A compression spring substantially as hereinbefore described with reference to the accompanying drawings.