The present invention relates to an apparatus and a method of inserting springs into positions between plies of pocketing material in the manufacture of pocketed spring units , for example as used in mattress cores .

Figure 1 shows schematically one previously considered method of manufacturing pocketed spring units , for use in mattress cores , according to our own earlier European Patent No . EP 1 993 947 B . The apparatus is shown generally at 100 . A row of coil springs S ( only the endmost spring of each row is visible in the drawing) is carried, under a degree of compression, into position by a pair of conveyor belts 110 . The springs are then urged from between the belts and inserted into place between superposed sheets 120 or webs of pocketing material supplied from reels 130 . A set of reciprocating pusher tools 140 (moving back and forth in the direction of Arrow Al ) pushes the springs S from between the belts . The pusher tools are connected to a common pusher driver 150 , which may be hydraulically or pneumatically actuated . Once the springs are in position between the sheets 120 , the material is indexed in the direction of Arrow A2 and an ultrasonic welding horn 160 travels down in the direction of Arrow A3 to press the sheets together against a welding anvil 170 to j oin the sheets at locations between the adj acent rows of springs .

The apparatus works reliably well and is widely used in the manufacture of certain types of pocketed spring . However, as the manufacturing process has increased in speed, the rate of insertion of the rows of springs into place between the sheets of pocketing material has been viewed as a potentially limiting factor .

Embodiments of the present invention aim to provide an apparatus and a method for inserting a row of springs into positions between sheets of pocketing material which is capable of increased speed and ef ficiency when compared with the prior art .

The present invention is defined in the attached independent claims , to which reference should now be made . Further, preferred features may be found in the sub-claims appended thereto .

According to one aspect of the present invention, there is provided a spring inserter apparatus , for inserting a spring from a spring conveyor into a position between plies of pocketing material in a pocketed spring unit manufacturing process , the apparatus comprising at least one spring inserter member arranged for reciprocal motion between a first , fully retracted position, in which the spring inserter member is positioned to push the spring into a position between plies of pocketing material , and a second, fully inserted position, in which the spring is placed fully between the plies , wherein the reciprocal motion of the spring inserter member is driven by a reciprocating driver to which the spring inserter member is connected via a linkage , and wherein for each motion cycle of the driver, the inserter member undergoes two full cycles of motion . The reciprocating driver preferably comprises a piston and, more preferably, comprises a pneumatic cylinder actuator .

In a preferred arrangement , the apparatus includes a plurality of spring inserter members arranged to push a plurality of springs from the conveyor into positions between the plies of pocketing material , which spring inserter members are connected to a common driver . The spring inserter members may be arranged to push the springs substantially simultaneously .

The motion of the driver is preferably in a first plane and the motion of the or each spring inserter i s in one or more respective second planes , wherein the first and second planes intersect , more preferably at substantially 90 degrees .

According to another aspect of the present invention, there is provided a method of inserting springs from a spring conveyor into a position between plies of pocketing material in a pocketed spring unit manufacturing process , the method comprising driving at least one spring inserter member into reciprocal motion between a first , fully retracted position, in which the spring inserter member is positioned to push the spring into a position between plies of pocketing material , and a second, fully inserted position, in which the spring is placed fully between the plies , wherein the reciprocal motion of the spring inserter member is driven by a reciprocating driver to which the spring inserter member is connected via a linkage , and wherein for each motion cycle of the driver, the inserter member undergoes two full cycles of motion . The invention may include any combination of the features or limitations referred to herein, except such a combination of features as are mutually exclus ive , or mutually inconsistent .

A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings , in which :

Figure 1 shows schematically a previously considered apparatus for inserting springs into position between superposed sheets of pocketing material ;

Figure 2 shows schematically in perspective view an apparatus for inserting springs in accordance with an embodiment of the present invention;

Figure 3 shows the apparatus of Figure 2 in schematic side view in a first stage of a cycle of operation;

Figure 4 shows the apparatus of Figures 2 and 3 in a second stage ; and

Figure 5 shows the apparatus of Figures 2-4 in a third stage .

Turning to Figure 2 , this shows , generally at 200 , a spring inserter apparatus according to an embodiment of the present invention . The apparatus 200 comprises a spring inserter member 210 , comprising a set of individual inserter fingers 212 attached to a common yoke 214 mounted on a sliding carriage 220 . A driver member 230 is connected to the carriage via a linkage 240 , which will be described below . The carriage 220 has a first mounting bracket 250 for securing to a spring pocketing station (not shown) and the driver member 230 has a second mounting bracket 260 for mounting to the pocketing station .

The driver member 230 comprises a pneumatically driven piston 232 within a cylinder 234 . The piston 232 moves reciprocally in a vertical plane ( i . e . up and down) . Its motion is converted by the linkage 240 into a reciprocal motion for the sliding carriage 220 and hence the yoke 241 and inserter fingers 212 which then move in a substantially hori zontal plane ( i . e . in and out ) to push a row of springs from between transportation belts into positions between plies of pocketing material (not shown) .

Turning to Figure 3 , this shows the apparatus in side view in a first configuration . The drive piston 232 is ful ly retracted in the cylinder 234 , the linkage 240 is at its lowest position and the fingers of the inserter are in a fully retracted position .

Figure 4 shows the apparatus in a second configuration in which the piston 232 is at hal f of its maximum extension, with the linkage 240 lying substantially hori zontal and parallel with the carriage 220 and the fingers 212 at maximum extension towards the springs (not shown) . Figure 5 shows the apparatus in a third configuration in which the drive piston 232 is at maximum extension, the linkage is at its uppermost position and the inserter fingers are again in a fully retracted position .

In use , the apparatus cycles through the first , second, and third configurations , before pausing to allow the next row of springs to be presented . Then, the apparatus cycles through the second and finally first configurations , pausing again for new springs to be presented . The cycle is then repeated, so that the inserter fingers move repeatedly in and out to push the springs into positions between the plies of pocketing material . The linkage converts the reciprocating motion of the drive piston 232 so that , for every one of its cycles , the carriage ( and hence the inserter fingers ) complete two cycles of in and out motion .

This allows for an ef ficient use of power to the drive piston, as it need only switch once between extension and retraction, for every two in and out operations of the inserter fingers . It also means that the speed of operation of the inserter mechanism can be increased, when compared with examples of the prior art .

In practice , the number of inserter fingers can be selected in accordance with the number of springs to be pushed by each apparatus 200 and several sets of the apparatus may be arranged side by side and under common control , to push longer rows of springs into pocketing positions at each cycle . Whilst endeavouring in the foregoing speci fication to draw attention to those features of the invention believed to be of particular importance , it should be understood that the applicant claims protection in respect of any patentable feature or combination of features referred to herein, and/or shown in the drawings , whether or not particular emphasis has been placed thereon .