GB2253219A

GB2253219A - Attachment wire and fabric structure for upholstery cover

Info

Publication number: GB2253219A
Application number: GB9204199A
Authority: GB
Inventors: Vincent Lee Brooks; Peter Desmond Kennedy; Clyde Esley Miller
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1991-03-01
Filing date: 1992-02-27
Publication date: 1992-09-02
Anticipated expiration: 2012-02-27
Also published as: GB2253219B; GB9204199D0

Abstract

An upholstered fabric structure eg a vehicle seat comprises a structural core (36) and a knitted fabric cover (35), the knitted fabric being of the double jersey type comprising a face layer (37) and a rear layer (38) and at least one tube (39) is formed within the body of the fabric between the rear and face layers to permit the insertion of a rod (42) to enable the fabric to be pulled into the structural core. The rod is formed of a metallic wire (42), eg steel, encased over substantially the whole of its length with a resilient material (43), eg a soft polymer. <IMAGE>

Description

Attachment Wire and Fabric Structure Incorporating such Wire This invention relates to attachment wires for the attachment of a knitted upholstery fabric to an upholstery core, and has particular reference to attachment wires for the attachment of knitted upholstery fabric intended to cover a three dimensional support such as a cushion of a vehicle seat, especially an automobile seat. The present invention also envisages an upholstered structure incorporating such attachment wires.

In European Patent Application 361,855, the contents of which are incorporated herein by way of reference, there is described the provision of integral tubular portions knitted into a double jersey structure machine knitted fabric, where such fabrics are particularly intended for use as vehicle seat bases and vehicle seat backs. The knitted tubular members may be knitted along the edges of the fabric structure or may be knitted integrally within the main portion of the fabric structure, as is illustrated in Figure 4 of the European patent application.

Described in European Patent Application 361,855 is a process whereby a metallic rod member is inserted into the tubular portion to permit attachment or tying down of the fabric to a base structure.

By the present invention there is provided an upholstered fabric structure including a core and a fabric cover in which there is provided a machine knitted upholstery fabric covering at least part of the surface of a three dimensional core wherein there is provided at least one portion of tubular fabric integrally knitted with the upholstery fabric cover and wherein there is provided an attachment wire located in the tubular portion in which the attachment wire is substantially wholly encased in a layer of resilient material.

The attachment wire may be a spring steel wire, and the resilient material may be a foam or a soft solid material.

The foam may be injection moulded around the wire. A suitable material for the resilient layer is a soft solids layer formed from ethylene propylene diene monomer.

The present invention further provides an upholstered fabric structure comprising a structural core and a knitted fabric cover, the knitted fabric being of the double jersey type and comprising a face layer of interengaging loops of yarn and a rear layer of interengaging loops of yarn, with a plurality of integrally formed yarn loops interengaging the face layer and rear layer over a substantial portion of the fabric, tubes formed within the body of the fabric between the rear and face layers to permit the insertion of rods to enable the fabric to be pulled into the structural core wherein the rods are formed of a metallic wire encased over substantially the whole of its length with a resilient material.

The present invention further provides an upholstered seat particularly for use in vehicles such as automobiles, in which the fabric of the seat is a machine knitted upholstery fabric which contains integrally formed tubular portions containing anchorage wires for securing the fabric to core of the seat wherein the anchorage wires are encased in a layer of resilient material.

The upholstered fabric may be a weft knitted double jersey fabric with the tubular portion being formed between the two faces of the fabric in a wale-wise direction, or in a course-wise direction. Alternatively the tubular portion may be formed by knitting extra courses on the back of the fabric to form the tube.

The present invention further provides an attachment wire tie down for an upholstery fabric, the wire tie down incorporating an elongate section and at least two loop engagement numbers, the elongate section being encased in a layer of resilient material having a thickness in the range 1 to 3 mm and a Shore A hardness in the range 15 to 50, preferably 20 to 40, further preferably 25 to 35.

The wires may have a substantially straight central portion with loops at each end. The loops may be free of resilient covering. There may be one or more loops of wire in the central portion. The central loops may be free of resilient covering.

The anchorage wires are preferably formed of cold drawn carbon steel wire of a springy form - typically cold drawn steel wire in accordance with BS 5216, further particularly such wire in accordance with BS 5216:1975 ND2.

Typically the resilient material will have a thickness in the range 1 to 2 mm, and the steel wire will have a diameter in the range 1.0 to 2.0 mm, preferably 1.5+ 0.25 Fm.

By way of example embodiments of the present invention will now be described with reference to the accompanying drawings of which Figure 1 is a schematic view of an upholstered seat cushion, Figure 2 is an underneath perspective view of a fabric containing an integral tube formed in a course-wise direction, Figure 3 is a plan view of a fabric with a tube formed in a wale-wise direction, Figure 4 is a stitch diagram of the fabric of Figure 3, Figure 5 is a sectional view of a prior art tie down, Figure 6 is a section view of a tie down not in accordance with the present invention, Figure 7 is a sectional view of a tie down in accordance with the present invention, Figure 8 is a schematic sectional view of a tie down arrangement in an upholstered structure, Figure 9 is a detailed perspective view of a tie down arrangement, and Figure 10 is a plan view partially broken away of a connecting wire in accordance with the present invention.

Referring to Figure 1, this shows an upholstered seat cushion or squab generally indicated by 1. The seat cushion is formed by the covering of a core 2 normally in the form of semi-rigid foam with a fabric cover generally indicated by 3.

The core 2 is shaped so as to provide wings, 4, or any other desired shape in the seat.

Such seats have particular application in vehicles but may be used in numerous other applications.

Stretched over the core 2 is a fabric cover 5, which is provided with a main body portion covering the seat with integral wing portions 6,7 and side portions such as portion 8. There is also a front portion 9 and the fabric cover is folded over the base of the seat squab and secured in a manner known per se.

Such seat structures are described in European Patent Application No. 361,855 referred to above. In that Application there is described a knitted fabric upholstery cover which is knitted in a single operation. To hold the seat cover firmly in place on the core and to provide attractive indentations in the seat cover such as the groove 10 there is described in the earlier European patent specification a method of integrally knitting a tubular portion such as the tubular portion 11 (Figure 2). The upholstery fabric generally indicated by 12 is formed of a double jersey type structure.A double jersey knitted structure is produced on a pair of opposed V-beds and may be regarded as a pair of single jersey knitted fabric layers each formed of a plurality of integrally connected loops or stitches in which the two fabric layers are interconnected by loops or stitches to form a double layered structure. The tubular members may be regarded as being formed by having regions where the interconnection between the face and rear layers has been omitted.

In the embodiment illustrated in Figure 2 the fabric has a wale-wise direction 13 and a course-wise direction 14. The knitted tubular loop 11 is produced by holding up the knitting on the face of the fabric whilst continuing to knit on the rear needle beds of the fabric to produce a larger rear fabric layer which is not interconnected to the face and hence forms the loop 11. Thus the portions 15 and 16 of the fabric have integrally formed double jersey layers 17 and 18 which are knitted together with interengaging loops. The tubular member 11 is produced by excessively knitting on the rear fabric layer whilst holding up the knitting on the front layer. It can be seen therefore that in the region of the tubular portion 19 the front knitted layer is very short whereas the rear knitted layer is very long and the tube can be as deep as desired. Continuing the knitting produces the wing 16 of the double jersey structure. It will be appreciated that the structure illustrated in Figure 2 is therefore a weft knitted structure knitted in the direction of arrow 13 with the wale direction in that direction and the course direction being in the direction of arrow 14 and lying substantially parallel to the longitudinal axis of the tubular member 11. Simple wire tie downs can be used in the course-wise tubular member 11.

However when tubes are produced in a wale-wise direction the tubular pocket cannot be knitted as deeply.

As shown in Figure 3 the fabric has a wale-wise direction 20 and a course-wise direction 22. The fabric is weft knitted on a flat V-bed knitting machine and a wale-wise direction tubular region 23 is produced by removing the interconnections between the front face and reverse face of the double jersey structure. Thus the edges 21,24 of the fabric are of double jersey structure whereas the region 23 comprises a tube of two layers of single jersey structure.

The fabric illustrated in Figure 3 is knitted in accordance with the stitch diagram shown in Figure 4. Figure 4 comprises a stitch diagram for 12 rows of stitching. The stitching is a four course repeat birds-eye-backed fabric structure containing a central tubular region between the lines A and B.

The stitch diagram illustrated in Figure 4 is of a conventional type in which each row labelled 1,2,3,4, 1,2,3,4, 1,2,3,4, represents an individual course or row of knitting.

In each row, such as row 1, the upper line of small dots represents individual needles on the rear bed of the knitting machine. Similarly the lower row of small dots represents the front bed of the knitting machine.

In the nomenclature used herein, the front face of the fabric is knitted on the front needles represented by the lower row of dots. The technical reverse face is knitted on the rear needle bed represented by the upper row of dots. The yarn which is knitted is represented by the loops and interconnecting lines such as loops 25,26 and interconnecting lines 27,28. The yarn which is knitted in the first course extends continuously from needle to needle passing from front bed to rear bed where illustrated for example at portion 28. In the case of the fabric knitted to the left of line A and to the right of line B, therefore, there is an interconnection between the fabric knitted on the front needle beds and the fabric knitted on the rear needle beds so that the two fabrics are joined together.

This is referred to as a double jersey knitted structure.

The second course, illustrated by reference number 2 on the left of the stitch diagram, represents the second layer of knitting knitted immediately after the first course. Course 2 may be knitted with the same yarn as is knitted on course 1 or may be knitted with a different yarn. In the case of course 2 only the rear needles are knitted upon and the second yarn is not knitted upon the front needles.

Considering the regions outside of the lines A and B courses 3 and 4 are identical to courses 1 and 2 save for the fact that they are displaced by one needle to the left or the right. This type of structure to the left and right of lines A and B is commonly referred to as a birds-eye-backed structure and it can be seen that in all 12 courses the structure simply repeats itself after every fourth course.

This structure is therefore referred to as a 4 course repeat structure. In Figure 4, 3 sets of the 4 courses are shown although as many courses as are required can be knitted.

Within the lines A and B, however, the knitted structure differs from that outside of those lines.

Referring to course 1 it can be seen that the yarn used to produce that course knits only on the front face. There is no interconnection between the front face and the rear face with the yarn knitting course 1. Similarly the yarn knitting course 2 knits only on the rear needle bed. Again there is no interconnection between the two needle beds in the second course. This knitting sequence is repeated in courses 3 and 4. Thus, in no case in either of the 4 courses, which are repeated throughout the structure, is there any interconnection between the fabric being knitted on the front needles and the fabric being knitted on the rear needles. In the absence of any interconnection between the two knitted structures, therefore, a tubular region is developed with a single jersey structure front and back and this corresponds to the tube 23 of Figure 3.

It will be appreciated that by virtue of the nature of the tubular region formed in a wale-wise direction the length of fabric in each face which forms the tube is the same.

Thus it is not possible to produce a tubular region similar to that illustrated in Figure 2 in which on the technical face of the fabric there is a substantially planar region, with a large tubular member formed on the reverse face of the fabric.

In the case of wale-wise formed tubes therefore prior art attachment systems may be inadequate.

The attachment of wires to a fabric upholstered structure is well known. Illustrated in Figure 5 is a system convcntionally used in the production of upholstered structures in which the fabric is a woven fabric. The fabric layer 29 is conventionally bonded to a resilient backing layer 30 which provides stiffness to the fabric and also acts as a padding. Stitched to the bottom of the fabric is a separate loop member indicated generally by 31. This loop member is stitched as at 32,33 to the woven fabric cover and forms a tubular pocket in which there is located a wire member 34 for attachment to the seat structure as will be described in more detail below.

It will be appreciated that the wire member 34 is fairly remote from the outer surface of the woven structure 29 and the backing layer 30 is located between the woven later 29 and the wire 34.

If the system adopted for fabric structures was utilised with knitted double jersey systems containing integral tubular attachment regions formed in a wale-wise direction as shown in Figures 3 and 4, then the structure illustrated in Figure 6, not in accordance with the present invention, would have been arrived at. In this structure it can be seen that the double jersey knitted upholstery fabric 35 has bonded to it a reinforcing layer 36 which again acts as a stiffening and padding layer similar to layer 30. However, the double jersey knitted structure 35 effectively comprises a face layer 37 and a rear layer 38 which are integrally knitted together over the bulk or the substantial part of the fabric. Where it is required to make attachment tubes the two layers are separated to form the tubular region such as the tube 39.If simply a wire 40 were to be inserted into the tubular region 39 it can be seen that there is then only a single jersey fabric layer 41 between the wire 40 and the outer face of the fabric.

There is therefore a risk that a person sitting on the seat could feel the wire 40 through the single jersey layer.

Illustrated in Figure 7 is a cross section of an attachment system in accordance with the present invention in which the same reference numerals have been used as appear in Figure 6 for equivalent parts. In this case, however there has been used a tie down wire in accordance with the present invention. The tie down wire comprises a steel core 42 surrounded by a resilient layer 43. The steel core is a cold drawn carbon steel wire in accordance with BS 5216:1975 ND2 having a diameter of 1.5 mm and being bright galvanised coated. The resilient layer 43 is a polymerised ethylene propylene diene monomer (EPDM) soft solid rubber material to specification SAEJ 200 BA305 having a Shore A hardness in the range 25 to 35. Because of the use of a soft solid rubber the metallic core 42 is well insulated from the user sitting on the seat who is then unable to detect the presence of the metallic core wire 42.

More details on the attachment method of the present invention can be understood with reference to Figures 8and 9.

In Figure 8 there is shown a sectional view of a seat squab essentially comprising a foam core 44 attached to a bottom framework 45 and containing a frame member 46 for attachment purposes. Surrounding the core 44 is a fabric cover 47 which contains a wire tie down 48. This is connected to the frame member 46 by means of metallic loops 49 (only one of which is shown). The structure is shown in more detail in Figure 9. It can be seen that an outer fabric layer 50 containing integral loops 51 has passing through it a foam covered wire 52 formed with protruding metallic regions 53. These regions are connected by loops 54 (which correspond to loops 49) and the loops 54 interlink the loop 53 with a frame portion 55 (which corresponds to the frame member 46).

A particular form of attachment wire is shown in Figure 10. From this it can be seen that there is a metallic wire member 56 consisting essentially of a straight portion having a pair of end loops 57,58 and in the particular embodiment illustrated a central loop 59. It can be seen that loop 59 is formed integrally from the wire which is shown dotted within the regions where the wire is encased within a soft solid resilient elastomeric material 60. Preferably a soft solid EPDM material is injection moulded around the wire 56 so as to be firmly bonded to the wire. This eases the insertion of the wire into the tubular portions of the upholstery fabric cover.

Course-wise tubes may also require cushioned wire tie downs if the tubes are small, and particularly if reinforcing backings are used over the course-wise tube, in which case excessively large tubes would make the application of a reinforcement or padded layer difficult.

Claims

1. An upholstered fabric structure comprising a structural core and a knitted fabric cover, the knitted fabric being of the double jersey type and comprising a face layer of interengaging loops of yarn and a rear layer of interengaging loops of yarn, with a plurality of integrally formed yarn loops interengaging the face layer and rear layer over a substantial portion of the fabric, at least one tube formed within the body of the fabric between the rear and face layers to permit the insertion of a rod to enable the fabric to be pulled into the structural core wherein the rod is formed of a metallic wire encased over substantially the whole of its length with a resilient material.

2. A structure as claimed in claim 1 in which the rod of metallic wire incorporates an elongate section and at least two loop engagement members.

3. A structure as claimed in claim 2 in which there is a loop engagement portion substantially in the middle of the metallic wire.

4. A structure as claimed in any one of claims 1 to 3 in which the wire is cold drawn carbon steel.

5. A structure as claimed in claim 4 in which the cold drawn steel is in accordance with BS 5216.

6. A structure as claimed in claim 4 in which the cold drawn steel is in accordance with BS 5216:1975 ND2.

7. A structure as claimed in any one of claims 4, 5 or 6 in which the steel wire has a diameter in the range 1.0 to 2.0 mm.

8. A structure as claimed in any one of claims 4, 5 or 6 in which the steel wire has a diameter of 1.5 + 0.25 mm.

9. A structure as claimed in any one of claims 1 or 4 to 8 in which the resilient material has a thickness in the range 1 to 3 mm.

10. A structure as claimed in any one of claims 1 to 9 in which the resilient material has a Shore A hardness in the range 15 to 50.

11. A structure as claimed in any one of claims 1 to 9 in which the resilient material has a Shore A hardness in the range 20 to 40.

12. A structure as claimed in any one of claims 1 to 9 in which the resilient material has a Shore A hardness in the range 25 to 35.

13. A structure as claimed in any one of claims 1 to 12 in which the resilient material is a soft polymeric material formed from ethylene propylene diene monomer.

14. A structure as claimed in any one of claims 1 to 13 in which the resilient material is a foamed material.

15. An upholstered structure as claimed in any one of claims 1 to 14 in the form of a seat.

16. An upholstered structure as claimed in claim 15 in which the seat is a vehicle seat.

17. An upholstered structure substantially as hereinbefore described with reference to Figures 1 to 4 and 7 to 10.