BACKGROUND

This invention relates to mattress manufacture and more particularly to a method and apparatus for mattress manufacture, particularly the manufacture of a resilient or spring core for mattresses specifically so-called "inner-spring" mattresses.

In the past, the manufacture of spring cores for mattresses has been undertaken on an substantially labour intensive basis and usually has involved the separate manufacture of compression mattress springs and the engagement of those springs into an internal "armature" using clipping means inter-clipping portions of the springs one with the other to form the armature. The armature or spring core usually has adhesive sheet fabrics with subsequent outer padding, for example sheet foam padding and the like positioned thereover with a ticking stitched thereover to encapsulate the spring core armature within the mattress and provide a flexible yet generally structural core for the mattress.

It will be appreciated that the manufacture of such mattress cores is quite time consuming, expensive and is suited more to individual or "piece" manufacture, rather than continuous flow production. Opportunities for increased speed of manufacture are limited, without the use of highly complex and expensive machinery.

Present machinery used in manufacture can in certain circumstances require high levels of maintenance and with lack of maintenance, downtime can be a problem.

Increasingly, there is also a customer need for mattresses to have the spring characteristics thereof "posturised" to the requirements of the user. Particularly with double beds there is a potential opportunity for posturisation as, almost inevitably, one bed partner requires posturisation of a different character to the other.

Further, there is a perceived opportunity for posturisation of the bed along its longitudinal axis to enable springing of greater deflection resistance to be used in the middle area of the mattress than the ends, on the basis that the torso/abdomen supporting area of the mattress is generally exposed to a higher level of weight than the head and legs supporting area.

Present manufacturing techniques do not lend themselves well to posturised manufacture without a significant element of hand manufacture. In most instances hand manufacture is found to be uneconomic for mainstream production.

The clipping arrangements for springs in traditional inner-spring mattresses also can lead, in certain instances, to difficulties of accurate spacing of

the springs and undesirable contact between springs in use, leading to noise and wear.

To some extent, these problems have been addressed in the manufacture of beds incorporating a sprung armature of springs enclosed within "spring pockets". Such spring pockets generally encapsulate each spring in a flexible cloth pocket and the cloth pockets are secured with other pockets and ultimately within padding on at least the upper part of the mattress, which is then housed within ticking.

Whilst pocket springing has provided enhanced spring placement/separation and to some extent has enabled more convenient posturisation of the mattresses, such manufacturing techniques are not suited to rapid and continuously manufacture without major investment in complex equipment .

Both of the methods of manufacture described hereinbefore, require the use of the glues, solvents and the like, for assembly and securement of the spring core within the mattress construction as a whole. With increasing environmental awareness, there is a need and desire in industry to reduce the level of use and dependence on such materials and also to reduce the need for safety isolating facilities in their use.

The substantially unitary manufacturing techniques used for mattresses and mattress cores have resulted in mainstream manufacture according to standard sizes. From a manufacturing point of view, even with standard sizes it is necessary for mattress manufacturing companies to keep on hand a stock of a variety of mattress spring core sizes to suit the manufacturing and ordering requirements. In view of the general bulk of such units storage problems can arise.

OBJECT OF THE INVENTION

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

Other objects of this invention will become apparent from the following description which is given by way of example with reference to one form of the invention. Modifications are envisaged and maybe incorporated without departing from the scope or spirit of the invention.

SUMMARY OF THE INVENTION

According to one aspect of this invention there is provided a method of manufacturing a spring core for a mattress including the step of engaging a plurality of mattress spring units in a portion of unset settable foam sheet material; and allowing said foam sheet material to set to thus engage said springs with said sheet .

According to a further aspect of this invention the method includes the step of forming a spring mattress core by foaming and supporting a foam sheet in an unset state on an first support means, supporting mattress springs in a disengageable manner on a second support means positioned adjacent said first support means and operating said assembly to bring said springs into engagement with portions of said unset foam sheets supported on said first support means and disengaging said springs from said second support means once engagement in said sheet is sufficient to support said spring engaged in said foam sheet .

According to a further aspect of this invention there is provided a means of forming a mattress core including a first conveyor adapted for supporting a sheet of foam material thereon in an unset state, a second conveyor positioned to co-act with said first conveyor and engage a plurality of mattress spring members in a predetermined pattern thereon via one end thereof and bring an opposite end thereof into engagement with the unset foam sheet supported on said first conveyor and to hold said engagement until a sufficient set has occurred to secure said spring end with said first foam sheet, to engage said spring units with said first foam sheet in a predetermined pattern.

According to a further aspect of this invention there is provided a spring core for a mattress including

at least one foam sheet having a plurality of mattress spring units engaged therewith, at least one of said mattress spring units being partially engaged within the foam sheet material, said foam sheet material having been formed in a settable material and said spring unit having been engaged therein whilst a portion of said foam sheet is unset .

Other aspects of this invention will become apparent from the following description. Modifications are envisaged and may be incorporated without departing from the scope or spirit of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

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

Figures 1 and 2 show, substantially diagrammatically in perspective and side view, the method and apparatus of this invention used in the manufacture or a mattress spring core including a plurality of mattress compression spring units having their end portions engaged and secured within portions of a foam sheet, such as a foam plastics sheets, forming the outer portions of said mattress spring core, said spring end portions being engaged within the foam sheet during a phase when the foam is unset .

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to the drawings, preferably the mattress core as indicated by arrow 1 is formed as a substantially continuous ribbon of a pair of spaced apart foam sheets 2. Spacing of the sheets 2 is controlled by mattress spring members 3, having their end portions 4 embedded into and secured into the foam sheets 2.

Whilst in the preferred form of the invention foam plastics is used, eg. polyurethene and the like the invention is not limited to such foam materials.

It will be appreciated that such a mattress core ribbon 1 can be arranged according to a standard size and preferably a width suited to the standard length of a traditional bed. In this arrangement the ribbon 1 can be cut transversely to the required size to define the mattress core as being for a single mattress, double or larger mattress, depending on manufacturing requirements for use .

In the preferred form of the invention, preferably a spring 3 position layout is such that the various required core sizes can be conveniently cut by slicing through the foam sheets 2 in an area between rows of springs 3 in the mattress core ribbon 1 without unduly exposing portions of the springs 3 in a manner not required.

In manufacture, as will be seen particularly from Figure 2, the manufacturing apparatus is indicated by arrow 10 includes a first support means; in this case a conveyor, 11 which preferably has a conveyor surface able to support a foam plastic sheet in a "green" or unset state.

Preferably and upstream end 12 of the first conveyor 11 is associated with a foam sheet manufacturing head 14 having a continuous foam outlet head which deposits a foam plastic sheet in the unset or "green" state onto the upstream end 12 of the first conveyor 11 which subsequently passes beneath "doctoring" arrangements 15 to control the thickness and characteristics of the sheet as it passes along the first conveyor 11 surface toward an "invert area" 16 where the direction of the first conveyor 11 preferably passes through an angular orientation, for example 180°; although this is not essential.

A second conveyor 17 is preferably mounted above the first conveyor 11 and is arranged to have a series of engagement means (not shown) for engaging one end 4b of a plurality of mattress springs 3 in a preferred and predetermined array. Preferably a plurality of springs 3 are arranged in rows of a similar width to that of the foam sheet 2. The disengageable engagement means (not shown) for securing the end portions 4b of the springs 3 securely therewith, but in a manner which they can be

readily disengaged therefrom towards a downstream portion of the conveyor 17 in use.

Although it is not shown, preferably the second conveyor 17 is arranged with a spring feeding mechanism which enables pre-εelection and control of the nature and characteristics of the springs 3 fed to the input end of the second conveyor 17, in this way springs 3 of a certain gauge or springing characteristics can be fed to certain areas of the conveyor in use and thus enable "posturisation" of the mattress core.

Preferably an invert portion of the second conveyor 17 is provided based slightly downstream of the foam head 14 such that as the second conveyor 17 inverts the springs 3 an outer end portion 4a of each spring 3 is inserted into the unset foam on the first conveyor 11 and as the first and second conveyors 11 and 17 continue to move in the direction of the arrows M of Figure 1, the springs 3 are held between the second conveyor 17 and the first conveyor 11 while at least partial setting of the foam sheet 2 on the first conveyor 11 takes place.

Preferably setting of the foam sheet on the first conveyor 11 is sufficiently complete by the time it reaches the invert portion 16 to at least partially hold the spring end portion 4a in engagement therewith.

Disengagement of the engaging means on the second conveyor 17 is arranged to occur just upstream of the invert portion 16 to enable continued carriage of the springs 3 via the at least partially set foam sheet 2 on the first conveyor 11.

A third conveyor 19 is preferably positioned directly beneath the first conveyor 11 and to operate in a direction substantially corresponding with that portion of the first conveyor 11.

Preferably an upstream end 20 of the third conveyor 19 is provided with a similar foam manufacturing assembly 21 to that described with reference to upstream end 12 of the first conveyor 11, such that the second foam assembly 21 will provide a second foam sheet for supporting by the third conveyor 19.

It will be appreciated that in much the same manner as described with reference to the second conveyor 17, ends 4b of the springs 3 are brought into engagement with the unset portions of the second foam sheet as the first foam sheet and springs engaged therewith pass around the invert portion 16 of the first conveyor 11.

As the assembly passes on the first conveyor 11 and third conveyor 19 to the discharge end d of the assembly, it will be appreciated that at least partial setting of the second foam sheet occurs, securing the spring ends 4b

therewith to form the resultant spring/foam sandwich for the mattress core 1.

Whilst the invention has been described with reference to a method and conveyor apparatus as shown diagrammatically in the attached drawings, it is to be appreciated that the use and orientation of the conveyors is not completely crucial, with the exception of the need to hold the relevant portions of the springs 3 to engage with the adjacent portions of the foam sheet 2 in contact for sufficient time for setting of the foam to occur for engagement .

The invention envisages the use of a substantially foamed plastic core, utilising foam plastics in the nature of polyurethene, together with springs formed from tempered steel or similar durable materials. The invention is not however limited to these materials and it is envisaged that alternative materials may be utilised, including certain other plastics/rubber foam materials and other metals, plastics and the like for springing.

It will be appreciated that by use of this method and apparatus, a spring foam core is produced which conveniently provides a unit for manufacture of mattresses of many different sizes and enables a secure engagement of springs without the need for adhesives and the like. The method also enables continuous manufacture

of the core at speeds which are limited only by foam setting characteristics, together with the speed of supply of mattress spring units.

It will be appreciated that whilst the invention is described with reference to apparatus and the resultant manufacture of a mattress foam core comprising a "closed" sandwich of a pair of foam sheets sandwiching mattress spring units therebetween. In an alternative arrangement it is envisaged that the mattress foam core can be provided as a substantially "one-sided" unit, such as with mattress spring units 3 engaged with one end portion 4 thereof engaged with the foam sheet 2 as hereinbefore described and the opposite end being substantially free. In such circumstances it is envisaged that the manufacturing apparatus of the invention may not include the invert 16 of the first conveyor 11 and the assembly in association with the third conveyor 19.

The preferred form of the invention envisages the engagement of springs with the foam sheets whilst the foam sheets are in an unset state by virtue of the foam having not yet set from manufacture. In alternative forms of the invention it is envisaged that the unset state of the foam maybe achieved, for example, by "unsetting" portions of the foam, for example by the application of heat to either the foam or portions of the spring, prior to or during engagement with subsequent "resetting" after engagement.

In this alternative embodiment it will be appreciated that foam plastics materials formed in a thermo-setting foam plastics material would be preferred.

Thus by this invention there is provided a method and apparatus for continuous spring mattress core manufacture and a method of manufacture of spring mattress cores.