GB2378959A

GB2378959A - Pattern sewing machine

Info

Publication number: GB2378959A
Application number: GB0219329A
Authority: GB
Inventors: Christopher Leslie Stratton; Stephen Mark Stratton; Kieron Knight
Original assignee: FOUNDATIONWEAR MACHINERY SPECI
Current assignee: FOUNDATIONWEAR MACHINERY SPECI
Priority date: 2001-08-22
Filing date: 2002-08-20
Publication date: 2003-02-26
Anticipated expiration: 2022-08-20
Also published as: GB0219329D0; GB2378959B

Abstract

A pattern sewing apparatus for sewing a pattern of stitchwork such as a series of tacks (fig 3) on textile fabric for a mattress border 15 comprises a sewing machine 12 and a feeding clamp having an upper plate 16 and a lower plate 18, each plate having an opening through which the pattern is sewn. The clamp advances the material towards the sewing machine 12 (direction B) and enables the fabric to be moved in any direction relative to the sewing machine 12 in accordance with the pattern to be sewn. A pneumatically actuated clamp (20, fig 4) is controllable to pull back the sewn material when the feeding clamp 16, 18 is open to compensate for any imbalances in pattern synchronisation. The apparatus also features guide-rails (36, figs 5 to 12) and sensors for detecting the layers of material (figs 14 to 17). The sewing head further comprises a circular presser foot and an air-jet to prevent the thread from being trapped (214, 228 fig 18).

Description

TITLE: APPARATUS FOR SEWING MATTRESS BORDERS DESCRIPTION The present invention relates to apparatus for sewing patterns on material of borders of mattresses, divans or the like. A mattress border is an edge or side panel which is sewn between upper and lower surfaces of the mattress.

A border for a mattress comprises multiple component layers which are stitched together to stabilise the border and to prevent the border collapsing. This may be achieved by hand stitching the border to an internal spring of the mattress, using side stitching, but this method is time consuming and expensive. On less expensive mattresses, the appearance of hand stitching is simulated but the stabilising effect is not necessarily achieved.

As an alternative to hand stitching, an apparatus is known which uses two modified sewing machines having

needles to apply tacks along two or three lines of stitching to join a fly panel 74 to the various component layers 82 of a border illustrated in Figure 13a. The fly panel may then be attached to springs in a bed whereby stability of the border may be provided.

The border material is fed from a roll held on a support stand, then fed under each sewing machine, and onto a spool which is driven by a winder device. Movement of the material in relation to the sewing machine is controlled by an indexing device which may advance or index the material to a required position under a needle of the sewing machine. The sewn border is then collected on the winder device. Material is drawn under the sewing machine and held stationary while the sewing machines move across the width of the material to apply two or three tacks. Once the tacks have been sewn, the indexing device advances, for example by 5cm, the next section of material under the sewing machine.

Before the component layers of the border are passed through the apparatus they may be pre-sewn together by an another machine. The machine may apply lines of stitching across the width of the border so as to define narrow troughs between broad peaks of material. A border having a similar peak 76 and trough 78 pattern is illustrated in Figure 13b. Two consecutive troughs define a standard spacing. For such pre-sewn materials, the apparatus may comprise a sensor which detects each trough and which is positioned the standard spacing in front of the needles.

Thus, when a sensor detects a trough, the needles automatically apply the tacks to the adjacent trough. However, there are variations in the standard spacing in each length of border and hence some tacks miss the trough and need to be reapplied.

Other known apparatus also comprises two sewing machines which are positioned side by side. Movement of the border material is also controlled by an indexing device and collection of the sewn border is on a winder device. The sewing machines move across the width of the material to apply tacks. The apparatus also comprises a clamp which holds the material in place during sewing, there is no lateral movement of the clamp.

In all the above apparatus, there is a requirement for movement of the sewing machine across the width of the border. The logistics of such movement and the size and weight of the sewing machines adversely affects the reliability and speed of operation. In general the known machines only apply single thread chain stitches which are a series of stitches formed by a single thread in which a succession of loops having the appearance of a chain are formed under the material. Such a stitch unravels easily. Furthermore, the sewing machines only move across the width of the border and thus there is little flexibility in the pattern to be applied. The apparatus is generally inefficient, slow and unreliable and there is a desire for an improved apparatus for sewing large volumes of border materials.

In accordance with the present invention, there is provided apparatus for sewing a pattern of stitchwork on textile fabric material for a mattress border, the apparatus comprising a sewing machine for sewing the pattern, feeding means for feeding material under the sewing machine, the feeding means comprising a clamp comprising an upper plate and a lower plate, the plates being configured to engage opposing sides of the textile fabric material, with the upper plate and lower plate having a window in which the pattern is sewn, and the lower plate being configured for supporting and guiding the material wherein the clamp is operable to advance the textile fabric material in a first direction towards the sewing machine and in any direction under the sewing machine in accordance with the pattern to be sewn with the clamp securing the material against movement relative thereto during sewing.

In contrast to known machines for sewing borders, any pattern of stitchwork may be applied. Movement of the material relative to the sewing machine is controlled by the clamp rather than an indexing device. The sewing machine may thus be stationary which allows for a more efficient operation. The movement of the clamp is determined by the pattern to be sewn and the pattern may be generated automatically. The use of the clamp provides greater freedom of movement of the material.

Furthermore, material handling and feeding is substantially automatic with only minimal involvement from

a manual operator. For example, the operator feeds an initial section of the material into the feeding means and thereafter the material is advanced or drawn towards the sewing machine automatically by the clamp. The material may be drawn from rolls and may be advanced towards the sewing machine intermittently or continuously.

Material may be advanced towards the sewing machine by moving the clamp to a first position spaced away from the sewing machine, activating the clamp, and moving the clamp to a second position in which the window is underneath the sewing machine and in which sewing of the pattern begins.

Material may be moved in accordance with the pattern to be sewn by moving the clamp from the second position to a third position in which sewing of the pattern finishes, the clamp remaining activated during sewing. The clamp may be released once sewing is completed and the clamp may be moved to the first position to repeat the cycle.

The apparatus may comprise a clamping device which is located downstream from the clamp and which is activated to control movement of the material when the clamp is released whereby drag on the material may be prevented or alleviated. The clamping device may be released when the clamp is applied so as to allow lateral movement of the material being sewn, e. g. by providing some slack. In this way, the clamping device may prevent or control any frictional or physical forces imposed against the material by the apparatus or the material itself.

The clamping device may comprise a clamping member,

e. g. bar, which engages an upper surface of the material and clamps the material against a surface, e. g. work surface, supporting the material. The clamping member may be moveable between a first open position spaced away from the material and a second closed position clamping the material to the work surface. Movement of the clamping bar may be powered by one or more pneumatic cylinders.

The clamping device may comprise a drag compensation member which is mounted between the clamping device and the clamp and is designed to compensate for any unwanted drag on the material by pulling newly sewn material towards the clamping device. Such drag may result from the elasticity of the fabric materials and the friction applied by the upper and lower plates of the clamp and may cause the pattern synchronisation to become unbalanced.

In other words the distance between the first stitch of the new sewing cycle and the last stitch of the previous sewing cycle may vary and may not be balanced with the pattern being sewn within the cycle.

The drag compensation member may be moved between a first position spaced away from the surface of the material to a second position which forces a section of material below the member into a corresponding channel in the work surface. The drag compensation member may be mounted, either directly or via a mounting member, to the clamping bar so as to allow relative movement between the drag compensation member and the clamping bar.

The drag compensation member and the clamping bar may

move simultaneously with movement provided by separate pneumatic cylinders. The operation of the cylinder moving the drag compensation member may be controlled by a valve which is activated by a sensor, e. g. when the sensor contacts the surface of the material. The sensor may be mounted to the valve or incorporated therein. The sensor may be mounted directly to the clamping bar whereby movement of the clamping bar from the open to the closed position brings the sensor into contact with the material.

The drag compensation member and/or the sensor may be mounted so as to permit height adjustment according to the thickness of the material.

The apparatus may be programmed to activate and release the clamping plates and/or the clamping device at predetermined activation and release trigger points in the sewing pattern. The clamping device is preferably activated as the clamp is released and vice versa. The clamping plates activation trigger point and/or the clamping device release trigger point may be located between the first two stitches of the sewing pattern. The clamping plates release trigger point and/or the clamping device activation trigger point may be located between the last two stitches of the sewing pattern. The first and last two stitches may be tacks which are respectively applied on opposed outer extremities of the pattern.

The size of the window and hence the clamp may be selected according to the pattern and/or material to be sewn. The pattern may extend across the width or length of

a border. The apparatus may be programmed to be fully automatic or to be semi-automatic with some manual control.

The sewing pattern may thus be of any design in contrast to previous machines which are designed only to sew tacks.

In contrast to previous machines which only apply single thread chain stitch, the sewing machine of the present invention may apply the stitch formation known as lock stitch. Lock stitch is a series of stitches formed by an upper thread and a lower thread being looped together with a lock of threads in each stitch. Such a formation of stitch unravels less easily than a single thread chain stitch. Lock stitch achieves a more secure stitch formation which is more suitable for the application.

The upper plate of the clamp may be configured for free movement across the material from the third position to the first position. The upper plate may thus comprise a raised leading edge and the window may have a chamfered trailing edge to provide free movement. The lower plate of the clamp may be configured for free movement under the material from the third position to the first position.

The material support may thus have a relatively smooth upper surface.

Movement of the clamp may be provided by a driving block integral to the sewing machine. The driving block may be attached to the clamp by a driving block clamp support. The driving block may move the clamp in any direction in a substantially horizontal plane, i. e. in a plane parallel to the clamp. The clamp support may comprise at least one air

cylinder which may provide substantial vertical movement of the upper plate of the clamp and hence substantial clamping pressure. The specification of the or each air cylinder may differ to that of conventional air cylinders which are normally fitted by a manufacturer of the machine whereby more lift to the upper clamp and increased pressure via the clamp on the material may be provided.

The border may comprise multiple layers of textile fabric material which are stitched together and fed from a single roll support. Alternatively, the border may comprise multiple separate layers of textile fabric material which may be fed from separate material roll supports. The material support may comprise at least one entry guide rail under which material is fed as the material enters the material support. There may be multiple entry guide rails, each set at a different height from the material support.

The material may be fed under a selected entry guide rail depending on the material thickness. Alternatively, each separate layer of textile fabric material may be fed under a separate entry guide rail.

The material support may also comprise an exit guide rail under which the material is fed as the material exits the material support. The height of the exit guide may be adjustable to match the thickness of the material and the entry guide rail selected. There may be multiple exit guides. A pair of material guides may be attached to each of the entry and exit guide rails to assist in controlling and guiding the material on the support. The position of

the material guides along the guide rails may be variable to define a span which matches the width of the material to be sewn. The provision of entry and exits guide rails means the material support may be regarded as a feed or guide palette for the material.

Both the entry and exit guide rails may be supported at one end by locating blocks and at the opposed end by hinge blocks. The guide rails may thus be pivotable about the hinge blocks between an open position spaced away from the locating blocks and a closed position located in the locating blocks. Material may be fed under the guide rails in the open position. The locating blocks may comprise grooves for supporting the guide rails and screws for releasably retaining the guide rails in the grooves.

The material support may be generally plate-like and may be formed with upturned edges for added strength. The material support may further comprise additional strengthening means, for example a strengthening bar mounted to an upturned edge. Alternatively or additionally, the material support may comprise strengthening spars mounted to the driving block. In view of the additional strengthening, the material support may be larger than conventional material supports.

The apparatus may comprise means to interrupt operation of the apparatus, in particular the sewing machine, if any one of the layers making up the border is missing or incorrectly aligned. The means may comprise at least one sensor monitoring each layer of material, the

sensor being arranged to send a signal which interrupts operation of the apparatus when the layer of material is not within the range of the sensor. The number of sensors may correspond to the number of layers. The sensors may be optical or mechanical. The sensors may be mounted so that the angle of each sensor and/or the distance between each sensor and the material may be adjusted, for example to suit the thickness of each layer. Such an interruption means may also be adapted for use on other similar apparatus, for example to sense the presence or absence of any component to be sewed.

A sewing machine, which may be used in the apparatus described above, may comprise a material compression device mounted under the needle and having an aperture through which the needle passes to sew tacks in the border, the shape of the compression device being selected so that the compressive force exerted on the layers of material underneath the device radiates to material surrounding the device. The compression device may be dished and the aperture may pass through the centre of the device.

A sewing machine, which may be used in the apparatus described above, may comprise a thread wiper which, after each tack has been sewn, wipes the thread tail extending from the needle. The sewing machine may comprise a blower which is connected to a fluid (e. g. gas) source and which has an outlet adjacent the needle point so that fluid blows the thread tail extending from the needle and induces it to rise above the surface of the layers of material. In this

way, the thread tail should not become trapped during movement of the border.

The sewn border may be collected on a winder device which may be controlled by trigger points within the sewing cycle. The winder device may be controlled by a timer which is activated by the trigger points. In this way, there is flexibility regarding the start time and duration of the operation of the winding device. The winding device may comprise a motor which drives a spindle or spool onto which the border is wound. A safety clutch may be fitted between the motor and the spindle to prevent over winding, particularly when the flow of finished border is interrupted, e. g. as a result of a malfunction in the sewing machine. Such a winding device may also be adapted for use on other sewing apparatus, for example to collect the sewn article.

The winder device provides an integrated means of collecting the sewn border. Thus, the flow of material into and out of the apparatus may be automatically controlled and involve no manual intervention which should reduce the risk of operator error.

A specific embodiment of the invention will now be described in detail, by way of example, and with reference to the accompanying drawings in which : Figures la and Ib are schematic plan and crosssectional views of apparatus according to the present invention ; Figures 2a and 2b are respective plan and side views

of an upper plate of a material clamp used in the apparatus of Figure 1 ; Figure 3 is a plan view of a stitching pattern created by the apparatus of Figure 1 ; Figures 4 and 4a are perspective views from both sides of a clamping device used in the apparatus of Figure 1 ; Figure 4b is a schematic cross section of the clamping device of Figures 4 and 4a; Figure 5a is a plan view of a lower plate of the clamp used in the apparatus of Figure 1 ; Figure 5b is a cross-section along line AA of Figure

Sa ; Figure 6 is a perspective view of an entry or exit guide rail of the apparatus of Figure Sa ; Figure 7 is a cross-section of a screw used in Figure Sa, 8 or 9; Figure 8 is a schematic perspective view of a first locating block for supporting an entry guide rail of Figure

5a ; Figure 9 is a schematic perspective view of a second locating block for supporting an exit guide rail of Figure Sa ; Figure 10 is a schematic perspective view of a first hinge block supporting an entry guide rail of Figure Sa ; Figure 11 is a schematic perspective view of a second hinge block supporting an exit guide rail of Figure Sa ; Figure 12 is a side view of the hinge block of Figure

Figure 13a and 13b are cross-sections of border before and after sewing by the apparatus of Figures 1 to 12; Figures 14a and 14b is a schematic plan and side views of apparatus according to the present invention showing the location of sensors which may be used in the apparatus; Figures 15 to 17 are perspective views of the sensors of Figure 14, and Figure 18 is a side view of the machine head of the sewing machine which may be used in the apparatus of Figures 1 to 17.

Figures 1 to 12 show apparatus 10 embodying the present invention. All elements in common between the Figures have the same reference numbers. Figure 13 shows a section of border before and after sewing by the apparatus of Figures 1 to 12 in which various component layers are visible.

Figures la and Ib show apparatus 10 which comprises a sewing machine which is supported on a main frame 70 and which has a machine head 12. Located underneath the machine head is a clamp comprising an upper plate 16 and a lower plate 18 and a machine bed plate 101 along which the clamp moves. The lower plate 18 acts as a material support for supporting material to be sewn into a border (not shown). The machine head 12 is held in a fixed position within the apparatus 10.

The clamp is mounted on a driving block 68 which is integral to the sewing machine and which is powered by a unit 102 connected to two motors. The power unit 102 moves

the driving block 68, and hence the clamp, in two perpendicular directions, i. e. in x-y axes, in a plane parallel to the plane of the clamp. The power unit 102 also comprises power and control hardware for driving the sewing machine. For example, one such known sewing machine with an integral driving block is from the"Brother" BAS- 300E series. Such a sewing machine has the necessary hardware and electronics to power and to move the clamp.

The border 15 comprises multiple layers of textile fabric material which are to be sewn together as shown in Figure 13a. Each layer of material is fed from a respective material roll holder 14 onto the support 18. The clamp draws the material from the roll holders under the sewing machine and secures it against movement during sewing.

The finished or sewn border 15 is wound onto a spool 21 by a winder device 22. Thus, the material flows across the machine bed plate 101 in the direction shown by arrow B, i. e. right to left in Figures la and lb. It is essential that there is a free path for drawing the material from its across the machine bed plate 101, particularly from source to sewing machine. At all times, including during feeding and sewing, a central axis of the border 15 is aligned with an axis 30 of the apparatus which is a central axis of the clamp. A clamping device 20 controls the position of the sewn border when the clamp is released. The clamping device 20 is mounted downstream of the clamp.

As shown in Figure lb, the upper and lower plates 16, 18 of the clamp are moveable from first positions which are

shown in dotted lines and which are spaced from the machine head 12 to second positions shown in solid lines. The second positions are adjacent the machine head 12 and represent the position in which sewing of the pattern begins. Movement of the clamp moves the material under the sewing head in accordance with the programmed pattern to a third position in which sewing of the pattern finishes.

When stitching is completed, the clamp is released and the upper and lower plates 16,18 are moved across the material to the first position which represents the next area to be sewn. The clamp is reapplied and the material is drawn by the movement of the upper and lower plates 16,18 towards the first position for the next sewing cycle. In other words the clamp automatically feeds the material from its source to the sewing machine.

The upper and lower plates 16,18 move in unison across the machine bed plate 101 to move material between the first, second and third positions. The lower plate 18 has a relatively smooth upper surface, i. e. polished, to enable the lower plate 18 to slide freely beneath the material when moving from the third to the first position. The lower plate 18 also has a relatively smooth lower surface to enable it to slide freely across the machine bed plate 101 which has a relatively smooth upper surface.

As shown in Figures 2a and 2b, the upper plate 16 of the clamp is plate-like, generally rectangular and defines a generally rectangular window 24 in which stitching of the border occurs. The leading edge 25 of the upper plate

is angled or raised and the trailing edge 26 of the upper plate is angled or chamfered. This allows free movement of the upper plate 16 over the material as the clamp moves between second and first positions.

Figure 3 shows a pattern of stitches or tacks 28 created by the machine head in the window 24 of the upper plate. The pattern of tacks 28 is programmed into a stitching cycle control program in the power unit 102. The power unit 102 moves the clamp relative to the machine head 12 according to the control program. Movement is in two perpendicular directions shown as x and y axes which are in a plane parallel to the plane of the clamp.

First and second trigger points 34,32 which are codes to control external devices, e. g. the clamping device 20, are also programmed into the stitching cycle control program. The location of the trigger points 34,32 depends on the programmed pattern of the tacks 28 but both trigger points are located on or not more than 25mm from the central axis of the border. By placing the trigger points close to the central axis of the border, the clamping device is less likely to skew the material on activation and thus skewing of the pattern of tacks will be minimised. The effect and location of each trigger point is described in the following steps (a) to (e). a) Tacks 28 are sewn symmetrically either side of the central axis 30 beginning with tacks 103 either side of a first or release trigger point 34 and finishing with tacks 104 either side of a second or activation

trigger point 32. Both the first and last sets of tacks are on the extremities of the pattern to be sewn. b) As the upper and lower plates 16,18 move the material through the second trigger point 32, the clamping device 20 is activated to secure the border prior to release of the clamp. c) Clamp is then released and upper and lower plates 16,18 move in unison across a predetermined length of material to the next portion to be sewn, i. e. to the first position. d) The clamp is reapplied and draws the next portion to be sewn under the machine head 12, i. e. the upper and lower plates 16,18 move to the second position. e) As the upper and lower plates 16,18 move the material through the first trigger point 34, the clamping device 20 is released. Sewn border may then be wound onto the spool by the winder device 22 since the material downstream of the clamp is free to move during the sewing of the pattern.

As shown in Figures 4 and 4a, the clamping device 20 comprises a clamping bar 64 in the form of an aluminium extrusion. The clamping bar 64 is moveable by two air cylinders 62 between a first, open position spaced away from the machine bed plate 101 and a second, closed position clamping the sewn border (not shown) against the machine bed plate 101. As the clamp moves the material through the second trigger point 32, the air cylinders

move the clamping bar 64 from the open to the closed position and vice versa as the clamp moves the material through the first trigger point 34.

The clamping device 20 further comprises a blade 204 which is mounted between the clamping device 20 and the clamp and is designed to compensate for any unwanted drag on the material. The blade 204 is supported on a mounting rod 203. Both the blade and the rod extend along the length of the clamping bar 64 but are not directly connected thereto as shown in Figure 4b. The blade 204 is moveable by a pair of pneumatic cylinders 206 which are supported on the clamping bar 64 by mounting blocks 210 and mounting plates 209 and the pistons 211 of which are connected to the mounting rod 203. Thus, the blade 204 is indirectly coupled to the clamping bar 64 so they have vertical synchronous movement. The mounting also allows the blade 204 to be moved independently of the clamping bar 64.

The pneumatic cylinders 206 are activated by a sensor 201 which is mounted underneath and controls a cylinder actuating valve 202. The sensor 201 is mounted on the opposed side of the clamping bar 64 to the blade. The sensor 201 is thus downstream of the clamping device to ensure that activation of the valve occurs only after the clamping bar 64 has clamping. In this way, the compensating effect is only applied to the material between the clamping bar 64 and the clamps and no sewn border may be unwound from the winder. The valve 202 is

mounted on the clamping bar 64 by a mounting bracket 212 which comprises a bolt and slot mechanism to adjust the height of the sensor to suit the material thickness.

As the air cylinders 62 move the clamping bar 64 from the open to the closed position, the sensor 201 is lowered to the surface of the sewn border. When the sensor 201 touches the surface, the valve 202 is released to activate the pneumatic cylinders 206. This drives the pistons 211, the mounting rod and hence the blade 204 down onto the surface of the sewn border. The downward motion of the blade 204 forces the section of the sewn border beneath the blade 204 into a channel 205 in a receiving member 231 which is attached to the main frame. The channel 205 has a length and breadth that is commensurate with the blade and the materials being clamped. Thus the sewn border is pulled back to compensate for any imbalance in the pattern synchronisation.

The amount the sewn border is pulled back is determined by the depth of the channel which is approximately 12mm deep, and how far the border is forced into the channel by the blade. Thus, the compensation by the blade is adjustable by appropriate setting of the height of the blade, the depth of the channel and by controlling the range of movement of the blade by the cylinders. The blade 204 comprises slots 213 into which bolts are inserted to fix the blade 204 to the mounting rod 203 and the bolt and slot mechanism allow fine adjustment of the height of blade 204. More significant

adjustment to the height of the blade, for example for a thicker material, may be achieved by varying the height of the mounting blocks 210.

As the clamp moves the material through the first trigger point 34, the clamping device 20 is released and the clamping bar 64 is raised. This lifts the sensor 201 above the surface of the sewn border which closes the valve 202 and deactivates the pneumatic cylinders 206.

The blade 204 thus returns to its raised position. The blade 204 is thus applied and released simultaneously with the clamping device and hence is applied and released in anti-phase with the clamp.

Figures 5a and 5b show the lower plate 18 of the clamp which is generally rectangular and which is platelike with upturned edges 38 for added strength. The lower plate 18 is formed with a window 19 which has the same dimensions as the window in the upper plate. The pattern of tacks 28 shown in Figure 3 is also created in the window 19 of the lower plate.

The lower plate 18 is mounted on a driving block 68 by two strengthening spars 46. The spars 46 are mounted to the driving block 68 by countersunk screws 48 which are longer than standard screws. The lower plate 18 is further strengthened by a strengthening bar which is clamped against the upturned edge 38 of the lower plate 18 by two screws 105. Both the lower plate 18 and the strengthening bar are secured to the driving block 68 by two screws 106.

The lower plate 18 acts as a material support and as a guide or feed palette for the material. Thus, the lower plate 18 comprises four guide rails 36, 37 which are in the form of bent bar hinges for easy loading of the material.

There are three entry guide rails 36 under which material is fed before sewing occurs and one exit guide rail 37 under which material is fed after it has been sewn.

Each guide rail 36, 37 is supported at opposed ends by a locating block 40, 41 and a hinge block 42, 43. The hinge blocks 42, 43 are located at the end adjacent the drive block 68. Each guide rail 36, 37 is pivotable about the respective hinge block 42, 43 between a first open position spaced away from the locating block and a second closed position in which the guide rail is located in the locating block. Material is fed under each guide rail when the guide rail is in the open position. Each guide rail 36, 37 is secured to respective locating block 40, 41 by a ball end retaining screw 50.

As shown in Figure 6, each guide rail comprises material guides 52 at locations spaced along the guide rail to assist the guidance and positioning of the component parts of the border. The span between the material guides 52 is adjustable and the height A of each material guide 52 is chosen according to component materials and to which guide rail they are mounted.

Figure 7 shows a ball end retaining screw 50 which is mounted in a bore as shown in Figures 8 and 9 to secure each guide rail to a respective locating block 40, 41. The

locating blocks 40, 41 comprise grooves 54 in which an end of a guide rail is located.

The first locating block 40 shown in Figure 8 has three grooves 54 and supports all three entry guide rails 37 which together with their respective material guides 52 control the material before sewing. The first locating block 40 has a stepped form whereby the three entry guide rails are set at different heights, with the guide rail closest to the sewing machine being the lowest. The material to be sewn is fed under only one guide rail depending on the thickness or bulk of the material. As a safety feature, if the material is too bulky to pass under a guide rail, the ball end retaining screw 50 retaining the guide rail is released. The guide rail is then rotated about the hinge support to the open position.

The second locating block 41 shown in Figure 9 is generally block-like with a single groove 54 to support the exit guide rail 37.

Figures 10 to 12 show the entry and exit guide rails 36, 37 supported in the hinge blocks 42, 43. As shown in Figure 10, the first hinge block 42 which supports the three entry guide rails 36 has a stepped form so as to match the varying heights of the guide rails set by the locating blocks. As shown in Figure 11, the second hinge block 43, for supporting the guide rail 37 also has a stepped form whereby a greater surface area for fixing the block to the material support 18 is provided. Figure 12 shows the hinge mechanism for the first hinge block, the

mechanism comprises a shaft 56, a washer 58 and a split pin 60. The mechanism for the second hinge block is identical.

Figure 13a shows a border before sewing comprising multiple layers of material 82 and a fly panel 74. Figure 13b shows the component layers after being passed through the machine of Figures 1 to 12. The tacks 28 holding the layers to create a surface effect having wide peaks 76 separated by narrow troughs 78.

Figures 14 to 17 show assemblies comprising sensors 215, 225 which detect the presence or absence of the various layers of material forming the border. As shown in Figure 14a, the sensors 215 are located between the material roll holders 14 and the main frame 70. The sensors are connected by mounting brackets 216 to the frame which supports the material roll holders 14. The number of sensors corresponds to the number of layers of material in the border. Thus as shown in the embodiment of Figure 14b, three sensors are mounted one above each other, i. e. vertically aligned with each other.

A layer of material is supported on a material support plate 219 and the sensors 215, 225 are suspended above the material supporting plates 219 on mounting brackets 216 attached to mounting blocks 217. Each individual layer of material is passed through its own corresponding sensor, i. e. between the mounting bracket 16 and the material support plates 219. The height of the mounting block 217 corresponds to the thickness of the material being sensed.

The mounting brackets further comprise a mechanism to adjust the angle of each sensor and to fine-tune the distance between each sensor and the material. Such a mechanism may be a pair of slots 230 in a downwardly extending portion of the generally L-shaped mounting brackets 216. The sensors 215,225 are mounted in the slots 230 by bolts 232 which may be set at the same height as in Figure 17 or at different heights as in Figures 15 and 16.

In Figures 15 and 16, the sensor 215 is mechanical and comprises an arm 229 which rests on the surface of the material (not shown). The mounting block 217 used to support the sensor of Figure 16 is larger than that of Figure 15 and thus the arm 229 is set at greater height above the material support plate. The arm 229 is inclined to the surface of the material. If the material is not underneath the arm, the arm 229 drops and this movement triggers an electronic switching device (not shown) which sends a warning signal to the power unit 102.

In Figure 17, the sensor 225 is optical and if the material is within the sensing range of the optical sensor 225, a warning signal is sent to the power unit. The warning signals of the sensors 215,225 indicate that the material has run out or become misaligned. The operation of the apparatus is interrupted or suspended until the fault is corrected. The apparatus will thus only operate if all the layers of material are within the sensing range of their respective sensors.

Figure 18 shows the machine head 12 of the sewing

machine. The machine head 12 comprises a needle 222 which passes through a central aperture 224 in a material compression device 214 to sew tacks in the layers of material below the compression device 214 and the needle 222. The machine head 12 also comprises an automatic integral thread trimming mechanism which after each tack has been sewn, cuts the thread on the underside of the material to leave a thread tail extending from the needle.

A thread wiper 220 wipes or pulls the thread tail from the surface of the material. The thread wiper 220 rotates about a pivot point 226 through say 120 degrees between a rest position which is spaced away from the tip of the needle and which is shown in Figure 18 and a wiping position adjacent the tip of the needle. When rotating from the rest to the wiping position, the wiper catches the thread tail and on the backward stroke, the thread tail is pulled away from the material.

The material compression device 214 may be connected to an actuating mechanism in a known manner so that when the actuating mechanism is engaged, the material compression device 214 is lowered to compress the layers of material. The compression device 214 rises when the actuating mechanism is disengaged. Lowering and raising of the device 214 via the actuating mechanism may be automatically controlled within the program cycle. Compression is exerted on the material both when the tack is being sewn and when the wiper 220 is moving between its rest and wiping positions. Pressure is relieved when the

material is being moved to another sewing position or when a new section of material is being transported into position to start a new sewing cycle.

The shape of the material compression device 214 is selected so the compressive force exerted on the layers of material underneath the device radiates to material surrounding the device. The compressive force is sufficient to prevent any cut thread from becoming trapped between the compression device 214 and the layers of material. The shape is also selected so as not to impede the sweeping motion of the wiper 220 as it rotates between its rest and wiping positions. The device 214 shown is generally bowl shaped but may be varied in both depth and width to ensure that the desired compressive force.

The machine head 12 also comprises a blower in the form of a pipe 218 which is connected to a fluid source, e. g. the pneumatic system controlling the clamping device.

Fluid, e. g. compressed air, is released from the outlet while the upper and lower plates of the clamp move between first and second positions, i. e. whilst the layers of material are being moved from a position adjacent the machine head to a sewing position underneath the machine head 12. The pipe 218 has its outlet 228 close to the point of the needle 222 so that the compressed air blows the thread tail extending from the needle and induces it to rise above the surface of the layers of material. This prevents the thread tail from becoming trapped.

The flow of compressed air is controlled by activation

or trigger points in the sewing cycle. For example, after each tack has been sewn the blower is activated whilst the clamp moves the material to the next sewing position. The blower is deactivated whilst a tack is being sewn.

Claims

CLAIMS 1. Apparatus for sewing a pattern of stitchwork on textile fabric material for a mattress border, the apparatus comprising a sewing machine for sewing the pattern, feeding means for feeding material under the sewing machine, the feeding means comprising a clamp having an upper plate and a lower plate, the plates being configured to engage opposing sides of the textile fabric material, with the upper plate and lower plate having a window in which the pattern is sewn, and the lower plate being configured for supporting and guiding the material wherein the clamp is operable to advance the textile fabric material in a first direction towards the sewing machine and in any direction under the sewing machine in accordance with the pattern to be sewn with the clamp securing the material against movement relative thereto during sewing.
2. Apparatus according to claim 1, comprising a clamping device which is located downstream from the clamp and which is activated to control movement of the material when the clamp is released.
3. Apparatus according to claim 2, wherein the clamping device is released when the clamp is applied so as to allow lateral movement of the material being sewn.
4. Apparatus according to claim 2 or claim 3, wherein the clamping device comprises a clamping member which engages an upper surface of the material and clamps the material against a surface supporting the material.
5. Apparatus according to any one of claims 2 to 4,

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wherein the clamping device comprises a drag compensation member which is mounted between the clamping device and the clamp.
6. Apparatus according to claim 5, wherein the drag compensation member is movable between a first position spaced away from the surface of the material to a second position which forces a section of material below the member into a corresponding channel in a surface supporting the material.
7. Apparatus according to claim 5 or claim 6, when dependent on claim 4, wherein the drag compensation member is mounted to the clamping bar so as to allow relative movement between the drag compensation member and the clamping bar.
8. Apparatus according to any one of claims 5 to 6 wherein the movement of the drag compensation member is be controlled by a valve which is activated by a sensor.
9. Apparatus according to any one of the preceding claims, wherein the apparatus is programmed to activate and release the upper and lower plates at predetermined activation and release trigger points in the sewing pattern.
10. Apparatus according to claim 9, wherein the activation trigger point is located between the first two stitches of the sewing pattern.
11. Apparatus according to claim 9 or claim 10, wherein the release trigger point is located between the last two stitches of the sewing pattern.

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12. Apparatus according to any one of claims 9 to 11, wherein clamping device is activated as the upper and lower plates is released and vice versa.
13. Apparatus according to any one of the preceding claims, wherein the sewing machine applies the stitch formation known as lock stitch.
14. Apparatus according to any one of the preceding claims, wherein the upper plate of the clamp is configured for free movement across the material.
15. Apparatus according to claim 14, wherein the upper plate comprises a raised leading edge and the window has a chamfered trailing edge to provide free movement.
16. Apparatus according to any one of the preceding claims, wherein the lower plate of the clamp is configured for free movement under the material.
17. Apparatus according to any one of the preceding claims, wherein movement of the clamp is provided by a driving block integral to the sewing machine, the driving block moving the clamp in any direction in a substantially horizontal plane.
18. Apparatus according to any one of the preceding claims, wherein the material support comprises at least one entry guide rail under which material is fed as the material enters the material support.
19. Apparatus according to claim 18, comprising more than one entry guide rail, each set at a different height from the material support, the material being fed under a selected entry guide rail depending on the material

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thickness.
20. Apparatus according to claim 18 or claim 19, wherein the material support comprises an exit guide rail under which the material is fed as the material exits the material support.
21. Apparatus according to claim 20, wherein the height of the exit guide is adjustable to match the thickness of the material and the entry guide rail selected.
22. Apparatus according to claim 20 or claim 21, wherein a pair of material guides is attached to each of the entry and exit guide rails to assist in controlling and guiding the material on the support.
23. Apparatus according to any one of claims 20 to 21, wherein both the entry and exit guide rails are supported at one end by locating blocks and at the opposed end by hinge blocks, the guide rails being pivotable about the hinge blocks between an open position spaced away from the locating blocks and a closed position located in the locating blocks.
24. Apparatus according to any one of the preceding claims, comprising means to interrupt operation of the apparatus, if a component layer of the border is missing or incorrectly aligned.
25. Apparatus according to claim 24, wherein the means comprises at least one sensor monitoring each component, the sensor being arranged to send a signal which interrupts operation of the apparatus when the component is not within the range of the sensor.

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26. Apparatus according to any one of the preceding claims, wherein the sewing machine comprises a needle and a material compression device which is mounted under the needle and which has an aperture through which the needle passes to sew the stitchwork pattern, the shape of the compression device being selected so that the compressive force exerted on the layers of material underneath the device radiates to material surrounding the device.
27. Apparatus according to any one of the preceding claims, wherein the sewing machine comprises a thread wiper which, after each discrete section of the stitchwork pattern has been sewn, wipes the thread tail extending from the needle.
28. Apparatus according to claim 27, wherein the sewing machine comprises a blower which is connected to a fluid source and which has an outlet adjacent the needle point so that fluid blows the thread tail extending from the needle and induces it to rise above the surface of the layers of material.
29. Apparatus according to any one of the preceding claims, wherein the sewn border is collected on a winder device the operation of which is controlled by trigger points within the sewing cycle.
30. Apparatus according to claim 29, wherein the winding device comprise a motor which drives a spindle onto which the border is wound and a safety clutch between the motor and the spindle to prevent over winding.