Transportation apparatus and method

Abstract

A conveyor (400) for transporting articles, such as coils springs, is described. The conveyor comprises a substrate (420) for supporting articles during transportation, and a plurality of retaining members (520) located on the substrate for retaining the articles during transportation. The retaining members (520) each comprise a mounting portion (530) for mounting to the substrate (420). A containment portion (540) comprises proximal and distal parts (540a) and (540b) define a space therebetween for receiving a coil spring (100) under compression. Slots (550a) and (550b) in the containment parts are aligned for receiving pushers.

Claims

1. A conveyor for transporting coil springs, the conveyor comprising a substrate for supporting springs during transportation, and a plurality of retaining members located on the substrate for retaining the springs on the substrate during transportation, wherein the retaining members each comprise a mounting portion for mounting to the substrate and a containment portion having proximal and distal parts defining a space therebetween for receiving at least a part of a spring under compression, and the retaining members are arranged such that each spring is held by a pair of adjacent retaining members.

2. A conveyor according to claim 1, wherein the retaining members are arranged in use to at least partly enclose the springs as they rest on the substrate.

3. A conveyor according to claim 1, wherein the retaining member comprises at least one slot, for receiving a displacement device, such as a mechanical pusher, arranged in use to displace the spring from the substrate.

4. A conveyor according to claim 1, wherein there is a plurality of retaining members spaced apart on the substrate along its axis.

5. A conveyor according to claim 4, wherein at least parts of adjacent retaining members are separated by a gap that is selected to accommodate depositing apparatus for depositing springs on the substrate.

6. A conveyor according to claim 1, wherein one or more of the retaining members is attached to the substrate.

7. A conveyor according to claim 1, wherein one or more of the retaining members is substantially integrally formed with the substrate, for example by moulding.

8. A conveyor according to claim 1, wherein the substrate comprises an endless belt or a chain.

9. A conveyor according to claim 1, wherein at least one coil spring is arranged to be retained in a retaining member such that coils at opposed ends of the spring are axially offset.

10. A method of transporting coil springs, the method comprising retaining the springs on a conveyor comprising a substrate for supporting the springs and a plurality of retaining members on the substrate, each retaining member comprising a mounting portion for mounting to the substrate and a containment portion having proximal and distal parts defining a space therebetween for receiving at least a part of a spring under compression, and the method includes retaining each spring by a pair of adjacent retaining members.

Description

(1) 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:

(2) FIG. 1 shows schematically a previously considered apparatus for pocketing springs;

(3) FIGS. 2 and 3 show part of a previously considered apparatus for depositing springs onto a conveyor;

(4) FIG. 4 shows schematically a conveyor transportation apparatus according to an embodiment of the present invention;

(5) FIG. 5 shows schematically a pre-compression apparatus for use with the conveyor of FIG. 4; and

(6) FIG. 6 shows schematically an alternative embodiment of spring transportation apparatus in accordance with the present invention.

(7) FIG. 1 shows schematically an example of apparatus described in the abovementioned patent, for making pocketed spring units for upholstered articles such as mattresses. Springs 100 are conveyed under compression to a spring-inserting position by an endless belt 110. The springs are trapped between the belt 110 and a low-friction plate 110a. Once at the pocketing station, the springs are pushed by mechanical pushers 120 that are driven by a motor 130 to move in a reciprocating motion, indicated by arrow A1.

(8) The pushers 120 push the springs into positions between sheets of material 130 fed from upper and lower supply rollers 140a and 140b via guide rollers 150a and 150b.

(9) The sheets 130 are joined at positions between springs by the reciprocating action of an upper welding tool 160a in the direction shown by arrow A2 that presses the sheets together and fuses them on a welding anvil 160b. A row of springs becomes encapsulated in pockets at each stepwise advancement of the resilient unit 170 in the direction of Arrow A3.

(10) FIG. 2 shows schematically a wheel apparatus 200 for depositing the springs onto the belt 110. The wheel has a plurality of spokes in the form of retractable rods 210. A coiling machine (not shown) loads a spring 100 onto each rod as the wheel turns in the direction of Arrow A4. The spokes then enter a compression zone 220, formed by two parallel tapering walls. The walls are spaced to allow the rod to pass between them but the springs are caught and gradually compressed as the rod progresses towards the bottom of the wheel.

(11) Then, when the spring is maximally compressed it is deposited onto a castellated conveyor belt 110 which carries the spring away in a direction substantially parallel with the axis of rotation of the wheel.

(12) FIG. 3 shows schematically the wheel viewed from the direction of Arrow A5 of FIG. 2. The figure shows the springs 100 being conveyed between the belt 110 and a low-friction plate 110a in the direction of Arrow A6, towards a pocketing station (not shown), such as is shown in FIG. 1.

(13) As previously mentioned, particularly when longer springs are used, or springs with more turns of wire, or else springs of relatively thin wire (smaller gauge), problems can arise during transportation. For example, if the spring is particularly stiff, the increased friction experienced as it slides along the plate 110a can sometimes cause the spring to bend or even to become dislodged as the belt moves. This can also happen when the spring is unstable, so that the force exerted by the belt is not fully transferred to the turns of wire located distally of the belt. Again the spring can bend and sometimes become dislodged.

(14) As well as potentially causing a spring to be omitted from the pocketed unit, this also leads to costly down-time for the pocketing machine as the missing spring must be located.

(15) Turning to FIG. 4, this shows generally at 400, in schematic part-sectional view, a conveyor according to an embodiment of the present invention. The conveyor 400 is suitable for use as spring transportation in a pocketed spring apparatus such as is described above with reference to FIG. 1 and can replace the belt/plate assembly 110/110a.

(16) The conveyor 400 comprises a substrate 410 (shown in cross section), in this case in the form of a castellated belt of nylon/plastics material, upon which are attached at equally spaced locations a plurality of retaining members 420 for securely retaining a number of springs 100 on the substrate.

(17) The retaining members comprise substantially T-shaped bodies of nylon/plastics material, each having a mounting portion 430 at its base that is mounted on the substrate. In this example the mounting portion straddles a castellation 410a of the substrate.

(18) The mounting portion extends away from the substrate and supports integrally formed, opposed containment portions 440 which extend substantially parallel to the substrate.

(19) Adjacent retaining members are spaced on the substrate by a gap G, which is sufficient to allow a rod 210 of a spring depositing wheel 200 (see FIG. 2) to pass therebetween, so that the spring becomes held on the substrate between opposed containment portions of adjacent retaining members, whilst remaining compressed.

(20) On each side of the retaining member, in a direction substantially parallel with the substrate, are located slots 450 for receiving pushers (e.g. 120 in FIG. 1) which travel transversely of the substrate to urge the spring from the substrate, at the point at which it is to be encapsulated in material. The height of the slot 450 is such as to provide space above the trapped spring. Meanwhile, the castellations of the substrate in this case provide space below the spring, such that a pusher that is taller than the height of the spring may be used.

(21) This allows the pusher to extend above and below the compressed spring to discourage or prevent the spring from becoming trapped above or below the pusher. A pair of pushers is used to eject a single spring by engaging the spring at two places on its radial periphery, and by sliding into the slots 450.

(22) In the example shown, the retaining members comprise discrete fixtures that are secured to the substrate from below by bolts 460. However, the retaining members could, as an alternative or in addition, be affixed to the substrate by another method, such as by adhesive. Indeed, the retaining members and the substrate could be formed integrally, such as by moulding.

(23) FIG. 5 shows a pre-compression apparatus for use with the apparatus of FIGS. 1-4. The schematic view is from above, looking down on a rod 210 of the wheel 200 of FIG. 2. A pair of rotating brushes, 500, are located one either side of the rod 210. The brushes are rotating in an opposite sense so as to push a spring 100 located on the rod 210. As the brushes rotate they tend to compress the spring so that prior to the spring entering the compression zone 220 of the wheel (see FIG. 2) the spring is already partly compressed.

(24) In use, the pre-compression apparatus 500 is deployed immediately prior to the rod entering the compression zone 220. This is useful, particularly with longer springs, to help accommodate them within the opening of the compression zone.

(25) FIG. 6 shows schematically an alternative embodiment of conveyor, in which retaining members 520, of a different shape to those of the FIG. 4 embodiment, are mounted on the substrate 410.

(26) In particular, the retaining members 520 each comprise a mounting portion 530 for mounting to the substrate 420. A containment portion 540 comprises proximal and distal parts 540a and 540b define a space therebetween for receiving a coil spring 100 under compression. Slots 550a and 550b in the containment parts are aligned for receiving pushers (e.g. 120 in FIG. 1) in a similar way as was described above in relation to the FIG. 4 embodiment. Again, the slots are of sufficient length to accommodate pushers that are taller than the height of the compressed spring.

(27) Again, the retaining members 520 may be secured to the substrate by suitable fixtures, as with the FIG. 4 embodiment (though omitted from FIG. 5).

(28) A first gap G1 between the distal containment parts 540a may be greater than a second gap G2 between the proximal containment parts 540b of adjacent retaining members. The first gap G1 is suitable for receiving a rod 210 of a spring depositing wheel 200 (FIG. 2). The second gap G2 can be smaller (as shown) or even substantially zero.

(29) In this embodiment the spring is contained by an adjacent pair of retaining members alone and does not rest against the substrate. This provides a number of advantages:

(30) Firstly, the compressed spring is no longer urging the retaining member and the substrate apart, which is useful for heavier gauge, or taller springs.

(31) Secondly, as the substrate plays no part in the retention of the spring, a single substrate may be used with differently sized retaining members, or retaining members arranged with different spacing, to accommodate springs of different diameters. Also, insertion and removal of springs does not cause any wear on the substrate, only on the retaining members which can be easily replaced.

(32) Furthermore, as the moving spring bears only against the proximal and distal containment parts of the blocks during insertion and removal, which parts are of a common material, there is no difference in the friction force experienced between the opposed ends of the spring, which could otherwise lead to an unintentional, or uncontrolled misalignment of the spring, and possibly a misfeed during pocketing.

(33) In one embodiment (not shown) at least some of the springs are held in the retaining members in a splayed configuration, such that adjacent coils are at least partly axially offset, rather than aligned in a cylindrical shape. In this configuration, when the spring is displaced from the retaining members it will automatically seek to re-orientate itself so that its longitudinal axis is transverse, more preferably substantially 90 degrees, to that which it was when it was held by the retaining member. This is useful in applications where it would otherwise be necessary to “turn” the spring in the pocket, to achieve the desired pocketing configuration.

(34) To achieve the splayed configuration one end of the spring may be at least partly or temporarily restrained or slowed with respect to the other as the spring is being inserted into the retaining member.

(35) Whilst the example described above is concerned with the transportation of springs, it will be understood by those skilled in the art that such transportation apparatus and method may be used to transport other articles.

(36) Whilst endeavouring in the foregoing specification 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.