GB2270296A - Assembly line system and pallet therefor. - Google Patents

Abstract

FIGURE 1 shows an assembly line system 1 having a pallet 2 travelling along work top 3a of work table section 3. Table section 3 has a track 3b along which a cardanic chain 4 moves to convey pucks 5 connected to the underside of the pallet 2 in spring-loaded manner, by means of frictional engagement between the chain and pucks. Pallet 2 is provided with a set of castors having resilient wheels 6a. Passageways 3c convey the pneumatic supply necessary for operating various items of equipment along the assembly line. The assembly line system also includes an adjustable track bend. In a modification the pucks 5 are locked in the track 3b (Fig 5). <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO ASSEMBLY LINE SYSTEMS This invention relates to improvements in or relating to assembly line systems, in which pallets or platens carrying workpieces are conveyed along an assembly line to work stations at which work operations are carried out on the workpieces.

In prior art assembly line systems workpieces are carried on pallets that run along an assembly line, the pallets have pucks which run in tracks, said pucks being in frictional engagement with a conveyor means usually in the form of a rubber belt or cardanic chain. It is believed that such systems tend to have disadvantageous features relating to cost ease operation of the assembly line apparatus, convenience of use and safety.

It is an object of the present invention to provide an assembly line system which is improved in at least some respect or which alleviates one or more of the aforementioned or other, disadvantages associated with such systems.

According to a first aspect of the present invention there is provided a pallet for an assembly line system said pallet having a plurality of castors or roller means arranged to run along a work table or work top of the assembly line system, said castors or roller means being inherently resilient or resiliently mounted on the pallet.

According to a second aspect of the present invention there is provided an assembly line system including a work top or table defining a track or slot for conveyor means that acts to convey pucks of a pallet along the work top/table by frictional engagement of the pucks with the conveyor means, the edges of the conveyor means being covered (preferably by flange means in the slot) or protected thereby preventing access to said edges whilst said pallet is conveyed along the assembly line.

Preferably, the pucks are locked in position for movement along said tracks/slots so that the pallet cannot be lifted from the work top/table. Removal of a pallet from the work table by an operator can cause problems in performing correct work operations in sequence on the pallets and this disadvantage can be substantially avoided by locking the pallets in position to run along the slots.

In order to check that no pallets have been removed from the assembly line it is necessary to tag each pallet uniquely which is more expensive than employing shift registers in the system. Such shift registers can be used reliably where the pallets are constrained to movement along the tracks/slots only.

According to a further aspect of the present invention there is provided an assembly line system including a work table or support having passageways extruded or formed therein for conveying air to pneumatic equipment of the assembly line system and/or for electrical cables. The passageways may or may not receive pneumatic tubing to carry the air. Preferably, passageways are provided to and from said pneumatic equipment in order to convey reclassified air away from said equipment.

According to a further aspect of the present invention there is provided an assembly line system including a worktop or table defining a track or slot for conveying means that acts to convey pucks of a pallet along the work top/table by frictional engagement of the pucks with the conveyor means, said pucks being locked in the track/slot for movement therealong.

According to a further aspect of the present invention there is provided an adjustable bend for an assembly line system, said bend being adjustable to allow pallets to be conveyed through a selected angle by conveyor means along an assembly line of the system.

According to a further aspect of the present invention there is provided a work top or work table for an assembly line system, comprising a track or slot to entrain pucks of a pallet to to move therealong said top or table comprising an assembly of a plurality of parts or extrusions which define opposite sides or side walls of the track or slot.

According to a further aspect of the present invention there is provided a puck for a pallet movable along a track or slot in a worktop or work table of an assembly line, said puck having a rotatable sleeve in order to reduce frictional effects on the puck should it contact a side or side wall of the track or slot, in use.

The present invention will now be described, by way of example only, with reference to the accompanying FIGURES of the drawings in which: FIGURE 1 shows a part-sectional view of a pallet positioned on a work table looking along the direct of conveyor means; FIGURE 2 shows a side view of the pallet looking in the direction of arrow A of FIGURE 1; FIGURE 3 shows a plan view of the pallet; FIGURE 4 shows on a larger scale, a section taken on line IV-IV of FIGURE 3; FIGURE 5 shows a view similar to the central region of FIGURE 1 but drawn to a larger scale and showing a modification; FIGURE 6 shows a fragmentary view of a modified table section, and FIGURES 7 and 8 show a plan and a side view of an adjustable track bend.

Referring more particularly to FIGURE 1, an assembly line system 1 shows a pallet 2 travelling along a work top or table top 3a of a work table section 3. The work table section 3 is a metal extrusion incorporating a track or slot 3b along which conveyor means in the form of a cardanic chain 4 moves in order to convey pucks 5 (only one shown in FIGURE 1) connected to the underside of the pallet 2 in a spring-loaded manner, by means of a frictional engagement between the chain and pucks.

Advantageously, the extruded section 3 includes cylindrical passageways 3c utilised for conveying the pneumatic supply necessary for operating various items of equipment (for example clamps) along the assembly line.

The passageways 3c of the extruded section 3 will be aligned with similar passageways in an adjoining table section and the pneumatic airline (for example rubber tubing having an outer diameter corresponding generally with the diameter of the passageway 3c) can be threaded through the aligned passageways. In this way, the pneumatic supply to various equipment along the assembly line can be constructed easily and safely and is arranged neatly out of the way of any of the parts of the assembly line. It may be that suitable sealing could be provided between the extruded table sections 3c linking together the passageways 3c rendering the provision of a separate tubing in the passageways unnecessary with rubber seals being provided between the sections 3c, the aligned passageways themselves providing the pneumatic ducting to service items of equipment.Additionally, and advantageously, the table section 3c is provided with ducts 3d as shown which are for electrical cabling appropriate to operation of the assembly line. Once again such ducting provides that the cabling can be neatly located and protected from other parts of the assembly line. The ducts 3d (and indeed the passageways 3c) are located on opposite sides of the track slots 3b near the sides of the table 3.

Advantageously, each pallet 2 is provided with a set of four castors or roller means 6 (see FIGURES 1,3 and 4) which act to help the pallet to run smoothly along the table top 3a as well as obviating the need for any reciprocable clamping means engaging the underside of the pallet during clamping at a work station.In prior art assembly line systems usually the pallets are not provided with castors or rollers and when it is desired to clamp a pallet at a work station so that an operation can be carried out on a workpiece (not shown) carried by the pallet, reciprocable pins are moved upwardly through the table top 3a to engage the underside of the pallet whilst clamping means 7 (see FIGURE 1) having tapered clamping heads 7a is moved vertically downwardly to seat in pallet bushes 2a in order to firmly hold the pallet whilst a work operation is carried out on a workpiece (not shown).

Providing the castors 6 (as shown) completely eliminates the need for providing the relatively expensive equipment (with reciprocable pins) required for engaging the underside of the pallet during such clamping operation.

Instead, the castors 6 have resilient wheels or rollers 6a mounted about axes 6b as shown, such wheels 6a being able to yield on application of a downward force of the pallet 2 by clamping means 7, enabling the pallet to be firmly clamped whilst the work operation is carried out on the workpiece. A fixed stop (not shown) may be provided for preventing a downward movement of the pallet 2 which is too great relative to the work table 3. As should be evident from FIGURES 1,3 and 4 the castor wheels or rollers 6a are able to rotate about axes 6b, said axes being arranged in a plane parallel to the pallet, and additionally each castor is rotatable about a vertical axis 6d. Thus each castor 6 is able to rotate about 2 axes. Further, the wheel or roller 6a of each castor 6 is mounted between two support members 6e on axles 6f each end of which is supported in an associated support member 6e.In one known prior art arrangement metal rollers are provided on the pallet which extend from opposite sides of the pallet rather than from the underside and these rollers have axles which are only supported at one end.

The rollers are metal and non-resilient and run in precision engineered tracks in the table top. However, in such systems when the pallet is clamped at the work station it is still necessary for vertically reciprocable equipment to be provided for engaging the underside of the pallet during clamping, said castors not being provided for the purpose of the present invention. Additionally, no tracks are necessary for the castors of the present invention. The present invention provides pallets which travel along the assembly line in a precision engineered manner without requiring the precision engineering necessary of the aforedescribed prior art system.

Referring more particularly to FIGURES 2 and 3, the pallet 2 has a front puck 5a provided with an elastic ring buffer B of advantageous form. The buffer B has an outer rubber elastic ring portion B1 integrally formed with an inner coaxial ring portion B2 joined to the outer ring portion B1 by two rearwardly curved wall portions B3 (see FIGURE 3). The inner diameter of the inner ring portion B2 corresponds with the outer diameter of stem portion S of the puck 5a which is assembled in the manner shown. A screw is located from the underside of the puck centrally of the stem S which screw into the underside of link arm A. The general form of the pallet 2 with pucks 5 and link arms A is generally known and thus will not be fully described here.The rear portion of the arresting buffer B is held by screws S1 and S2 (see FIGURE 2) and inner sleeve L so that the arresting buffer as a whole (and in particular the inner ring portion B2) resists rotation about the axis 5b of the puck. Thus, during travel of the pallet 2 should the arresting buffer meet with the force F in the direction as shown more particularly in FIGURE 3, the outer elastic ring portion B1 deforms in a resilient cushioning manner until the inner straight edge portion B1' engages the outer periphery of the inner elastic ring portion B2.Thus, the outer elastic ring portion B1 deforms to a generally squashed oval shape increasing its dimension across the table top track or slot 3b, frictionally engaging the side walls of the slot W to halt the progress of the pallet. It is believed that this form of elastic buffer is of a particularly advantageous and effective design.

A second spring-loaded puck 5 is provided spaced from puck 5a at the opposite end of link arm A and, advantageously, this puck is provided with a sleeve P1 rotatable relative to the puck body P2 of top-hat shape.

Should the puck 5 contact the side walls of the slot 3b the sleeve P1 is free to rotate reducing frictional effects and increasing the smooth travel of the pallet along the assembly line. As shown in FIGURE 2 a pair of pucks 5 is also proved at the rear of the pallet 2 on a second link arm A and each of these is provided with a rotatable sleeve P1, the most forward puck being springloaded.

FIGURE 5 shows an enlarged central region of FIGURE 1 which has been modified advantageously so that the normally exposed edges of the cardanic chain 4 are covered all the way along the slot 3b by overhanging strips E of L-shaped cross section. The arrangement as shown in FIGURE 5 advantageously increases the safety of the assembly line system by a large factor since access to the exposed edges of the chain 4 can be dangerous and such access is now precluded by the arrangement shown in FIGURE 5. Additionally, it will be noted that the strips E have horizontal edge surfaces El which act to retain the pucks 5' lockingly in the slot 3b with an annular shoulder 5a' being formed on the puck 5' extending underneath the edge surfaces El in a manner which should be evident from FIGURE 5. Advantageously, freely rotatable sleeve P1 is provided on puck body P2'. Instead of providing a single aluminium extrusion incorporating the slot 3b (as in FIGURE 1) now three aluminium extrusions Al, A2 and A3 are provided in order to solve the engineering problem of designing the work table to cover the edges of the cardanic chain and retain the pucks 5' in the slot 3b thus retaining the pallets to the work table whilst allowing motion along the slot 3b. Extrusions Al and A2 are similar and comprise opposite sides of the slot 3b.

Extrusion A3 comprises a piece bridging the gap between extrusions Al and A2 as shown in FIGURE 5. Longitudinal plates A4 and A5 are secured to respective side portions Al' and A2' of the extrusions Al and A2 as well as to respective side portions A3' and A3" of the extrusion A3 by respective screws or fasteners. It is believed that the particular way of forming the worktable from three extruded sections rather than one allows easier assembly thereof, and ease of manufacturing and allows advantageous safety features to be provided without large additional costs being involved. Also, such a construction allows the worktable to be more easily disassembled and stored should the need arise.It is possible that two rather than three extrusions might be provided in order to accomplish the same result as the three shown in FIGURE 5 with the worktable being split into two halves along the central line X-X of the puck shown in FIGURE 5.

Most importantly, it has been realised that the extrusion configuration A1,A2,A3 allows a much more versatile approach to the construction of assembly line systems. For example, extrusion A2 could be easily removed from the extrusion assembly which could then be interfaced with any other suitable module or cell components such as shown in our co-pending Patent Application of even date (see in particular pages 16 to 18), the content of the specification of which is hereby incorporated into this patent specification by reference.

FIGURE 6 shows a modified part Z of section 3 having two passageways 3'c (for incoming and outgoing or reclassified air) on one side of the slot 3b. The fragmentary part Z to the left of the slot 3b is shown in FIGURE 6 and it is to be understood that a corresponding pair of air passageways will be formed in a part (not shown) on the right of the slot as a mirror image of part Z.

FIGURES 7 and 8 show simplified views of an adjustable track bend 100 in which the angle thereof, and thus the angle through which a pallet is conveyed, is variable. The track bend 100 has two similar parts 101, 102 arranged to be pivotable relative to one another about vertical axis 103a (provided by pin 103) on circular stepped platform 103b. Ball bearings b are provided around pin 103 in a cylindrical portion of platform 103b.

The parts 101, 102 are shown arranged relative to one another in such manner that a pallet travelling in direction 104 will be conveyed smoothly around bend 100 so that the pallet direction is reversed along direction 105, which is parallel to direction 104. As should be evident from FIGURE 7, a stop 106 on part 101 extends into an arcuate slot 107 provided on part 102. Thus, from the position as shown, parts 101, 102 can be selectively rotated towards one another (ends 108, 109 being brought nearer to one another) by a maximum 30 (stop 106 engages end 110 of slot 107) or away from one another by a maximum of 1500 (end 111 of slot 107 engages the stop 106). Ends 108, 109 are shaped to interface with the associated ends of a track section 3 and can be secured thereto by releasable fastening means at fastening locations 112.

It is to be understood that the scope of the present invention is not to be unduly limited by the particular choice of terminology and that a specific term may be replaced by any equivalent or generic term. Further it is to be understood that individual features, method or functions related to the assembly line system or individual parts thereof might be individually patentably inventive. The singular may include the plural and vice versa.

Claims (39)

1. A pallet for an assembly line system, said pallet having a plurality of castors or roller means arranged to run along a work table or work top of the assembly line system, said castors or roller means being inherently resilient or resiliently mounted on the pallet.

2. A pallet as claimed in Claim 1 having four castors or roller means.

3. A pallet as claimed in Claim 1 or Claim 2 in which each castor or roller means is rotatable about two axes.

4. A pallet as claimed in Claim 3 in which one of said axes lies in a plane parallel to the pallet and the other axis is arranged at right angles to said plane.

5. A pallet as claimed in any one of the preceding claims in which a wheel or roller of each castor/roller means is mounted between two support members on axles, each end of which is supported by an associated support member.

6. A pallet as claimed in any one of the preceding claims in which the castors/roller means extend from the underside of the pallet.

7. A pallet for an assembly line, substantially as herein described with reference to FIGURES 1,3 and 4 of the accompanying drawings.

8. An assembly line system comprising at least one pallet as claimed in any one of the preceeding claims and a fixed stop limiting downward movement of a pallet at a work station.

9. An assembly line system including a work top or table defining a track or slot for conveyor means that acts, in use, to convey pucks of a pallet along the work top/table by frictional engagement of the pucks with the conveyor means, the edges of the conveyor means being covered or protected, thereby preventing access to said edges whilst said pallet is conveyed along the assembly line.

10. A system as claimed in Claim 9 in which the edges of the conveyor means are covered by flange means in the slot.

11. A system as claimed in Claim 9 or Claim 10 in which, in use, the pucks are locked in position for movement along said tracks/slots.

12. A system as claimed in any one of Claims 9 to 11 including shift registers.

13. A system as claimed in any one of Claims 9 to 12 in which the worktable is a metal extrusion.

14. A system as claimed in any one of Claims 9 to 13 in which the conveyor means is a cardanic chain.

15. A system as claimed in any one of Claims 9 to 14 including passageways in the worktable for pneumatic supply to equipment along the assembly line.

16. A system as claimed in any one of Claims 9 to 15 in which the work table includes ducts for electric cables.

17. A system as claimed in Claim 15 or Claim 16 in which the passageways or ducts are located on opposite sides of the track/slot.

18. A system as claimed in Claim 10 or any claim dependent therefrom comprising overhanging strips of Lshaped cross section.

19. A system as claimed in Claim 18 when dependent from Claim 11 in which the strips have horizontal edge surfaces which act to retain pucks of a pallet lockingly in the track/slotO

20. A system as claimed in any one of Claims 9 to 19 in which the edges of the conveyor means are covered all the way along the track/slot.

21. A system as claimed in Claim 9 in which the edges of the conveyor means are covered substantially as herein described with reference to FIGURE 5 of the accompanying drawings.

22. An assembly line system including a work table or support having passageways extruded or formed therein for conveying air to pneumatic equipment of the assembly line system and/or for electrical cables.

23. A system as claimed in Claim 22 in which the passageways are provided to and from said pneumatic equipment in order to convey reclassified air away from said equipment.

24. A system as claimed in Claim 22 or 23 in which the passageways are aligned with similar passageways in adjoining table sections with sealing being provided between the table sections.

25. A system as claimed in any one of Claims 22 to 24 having two passageways, for incoming and outgoing air respectively, on one side of a track/slot along which pucks of a pallet are conveyed.

26. A system as claimed in Claim 22 in which the passageways are substantially as herein described with reference to FIGURES 1 or 6 of the accompanying drawings.

27. An assembly line system including a work top or table defining a track or slot for conveying means that acts to convey pucks of a pallet along the work top/table by frictional engagement of the pucks with the conveyor means, said pucks being locked in the track/slot for movement therealong.

28. A system as claimed in Claim 27 in which the pucks are locked in position in the slots by strips of L-shaped cross section overhanging edges of the conveyor means.

29. A system as claimed in Claim 28 in which horizontal edge surfaces of the strips retain the pucks locked in position.

30. A system as claimed in Claim 27 in which the pucks are locked in the track/slot in a manner substantially as herein described with reference to FIGURE 6 of the accompanying drawings.

31. According to a further aspect of the present invention there is provided an adjustable bend for an assembly line system, said bend being adjustable to allow pallets to be conveyed through a selected angle by conveyor means along an assembly line of the system.

32. A bend as claimed in Claim 31 comprising two similar parts pivotable relative to one another, in use, about a vertical axis.

33. A bend as claimed in Claim 32 having a stop on one of said parts extending into an arcuate slot on the other part to limit the angular setting of said bend.

34. A bend as claimed in Claim 31 and substantially as herein described with reference to FIGURES 7 and 8 of the accompanying drawings.

35. A work top or work table for an assembly line system, comprising a track or slot to entrain pucks of a pallet to to move therealong said top or table comprising an assembly of a plurality of parts or extrusions which define opposite sides or side walls of the track or slot.

36. A puck for a pallet movable along a track or slot in a worktop or work table of an assembly line, said puck having a rotatable sleeve in order to reduce frictional effects on the puck should it contact a side or side wall of the track or slot, in use.

37. A puck as claimed in Claim 36 in which the puck body is of top hat shape.

38. A puck as claimed in Claim 36 substantially as herein described with reference to FIGURES 2 and 3 of the accompanying drawings.

39. An assembly line system substantially as herein described with reference to the accompanying drawings.