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Title:
CHAIN SYSTEM
Document Type and Number:
WIPO Patent Application WO/2008/104798
Kind Code:
A1
Abstract:
A chain system has a chain (50) formed from a series of six or more similar links (10) that are connected for rotation about pivot points (11, 12) provided at the end of each link (10) so as to form a continuous moveable loop, wherein the pitch (p) of the chain (50) is defined as the distance between the adjacent pivot points (11, 12) and is constant though out, characterised in that said chain (50) is constrained such that the centre point (15) of the links (10), being defined as the midpoint of the line joining the centre of the pivot points (11, 12) on the link (10), moves through a continuous closed defined path, wherein the path is specified as comprising two equal parallel straight sections and two equal semicircle sections, smoothly connecting the ends of the straight sections, so that the distance apart of the equal parallel straight sections equals the diameter of the semicircular sections and is equal to the pitch (p) of the chain (50).

Inventors:
PARSONS BRYAN NIGEL VICTOR (GB)
Application Number:
PCT/GB2008/000720
Publication Date:
September 04, 2008
Filing Date:
February 29, 2008
Export Citation:
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Assignee:
PARSONS BRYAN NIGEL VICTOR (GB)
International Classes:
B65G21/22; B65G17/06; B65G17/16
Foreign References:
US6269937B12001-08-07
US5188219A1993-02-23
GB1008836A1965-11-03
FR1406399A1965-07-16
DE3234817A11984-03-22
US3501996A1970-03-24
US5170006A1992-12-08
US6070716A2000-06-06
Attorney, Agent or Firm:
WATTS, Peter, Graham (39/41 South DriveSutton Coldfield, West Midlands B75 7TE, GB)
Download PDF:
Claims:

Claims

1 . A chain system comprising a chain (50) formed from a series of six or more similar links (10; 20; 103; 1 12) that are connected for rotation about pivot points (1 1 ,1 2) provided at the end of each link (10; 20; 103; 1 12) so as to form a continuous moveable loop, wherein the pitch (p) of the chain (50) is defined as the distance between the adjacent pivot points (1 1 , 1 2) and is constant though out, characterised in that said chain is constrained such that the centre point (1 5) of the links (10; 20;103;1 12), being defined as the midpoint of the line joining the centre of the pivot points (1 1 , 12) on the link (10; 20; 103;1 1 2), moves through a continuous closed defined path, wherein the path is specified as comprising two equal parallel straight sections and two equal semicircle sections, smoothly connecting the ends of the straight sections, so that the distance apart of the equal parallel straight sections equals the diameter of the semicircular sections and is equal to the pitch (p) of the chain (50).

2. A chain system according to claim 1 characterised in that the links (10; 20; 103; 1 12) are constrained to follow said two equal parallel straight sections.

3. A chain system according to claim 2 characterised in that, extensions of link pins (1 1 ) extend laterally from the links (10; 20;103;1 1 2) to engage a pair of parallel guide rails (30).

4. A chain system according to claim 3 characterised in that the length of the guide rails (30) is equal to the length (L) of the straight sections of the path plus the pitch (p) of the links (10; 20;103;1 12).

5. A chain system according to any one of the preceding claims characterised in that the links (10; 20;103;1 12) are unconstrained at the ends of the straight sections of the path, movement of the links (33,34) at the ends of the path being controlled by constraint of movement of the links (10; 20;103; 1 12) along the straight lengths of the path.

6. A chain system according to any one of claims 1 to 4 characterised in that the a pair of positioning links (41 ,42,43,44) are provided at each end of the path, each pair of positioning links (41 ,42;43,44) being independently mounted for rotation on a pivot pin, the pivot pin being located concentrically of the semicircular end section of the path, the lengths of said positioning links (41 ,42,43,44) being equal to the pitch (p) of the links (10;20;103; 1 1 2), arcuate cups being provided at the ends of the positioning links (41 ,42;43,44), for engagement if pivot formations (1 5) on the centre point of the links ( 10; 20; 103; 1 12), the positioning links (41 ,42,43,44) of each pair (41 ,42) ,(43,44) engaging the pivot formations ( 1 5) on alternative links (10; 20; 103; 1 12), to guide the links (10; 20;103;1 1 2) around the semicircular end section of the path.

7. A chain system according to any one of the preceding claims characterised in that the chain (50) is driven by one or more sprockets (60) which engage the chain 50 at a position on the straight section of the path.

8. A chain system according to claim 7 characterised in that the or each sprocket (60) engages both parallel straight sections of the chain (50) to drive both sections and provide a positive conjugate drive.

9. A chain system according to claim 7 or 8 characterised in that the or each sprocket (60) has a plurality of teeth of involute form.

10. A chain system according to any one of claims 7 to 9 characterised in that the or each sprocket (60) engages a tooth form on each of the links (10; 20;103;1 12), said tooth forms of the links (10; 20; 103; 1 12) in the straight sections of the path corresponding to a straight rack.

1 1 . A chain system according to any one of claims 7 to 9 characterised in that the or each sprocket (60) engages with circular pins on the links (10; 20;103;1 12) .

12. A chain system according to any one of the preceding claims characterised in that the links (20) are in the form of platens, the platens being pivotably interconnected along one longitudinal edge.

13. A chain system according to claim 1 2 characterised in that each platen is provided with one or more support rollers, said support rollers being adapted to engage a support surface in order to bear the weight of the platen and any load supported thereby.

14. A chain system according to any one of the preceding claims characterised in that the links (103) are of triangular configuration.

15. A chain system according to any one of the preceding claims characterised in that the chain system is utilised to form a conveyer system for components, people or other use.

16. A chain system according to claim 1 5 characterised in that platen type links (20) are used to provide a passenger conveyer.

17. A chain system according to claim 15 characterised in that pallets, storage boxes trays, hangers or other fitments (101 ) are attached to the links (10; 20;103; 1 12).

18. A chain system according to claim 1 7 characterised in that pallets, storage boxes trays, hangers or other fitments (101 ) are attached to individual links (10; 20;103;1 1 2).

19. A chain system according to claim 18 characterised in that one or more links do not have a pallets, storage boxes trays, hangers or other fitments (101 ) attached thereto, so that in a stationary position of the chain system, a pallet, storage box, tray, hanger or other fitment (101 ) will not be attached to the link (10; 20; 103; 1 12) positioned at an end of the path of the chain (50).

20. A chain system according to claim 19 characterised in that pallets, storage boxes trays, hangers or other fitments ( 101 ) are attached to alternate individual links (10; 20; 103; 1 12).

21 . A chain system according to any one of claims 18 to 20 characterised in that pallets, storage boxes trays, hangers or other fitments (101 ) are pivotally attached to the links (1 1 2) so that they may rotate relative to the links (1 12) and maintain their orientation as the pallets, storage boxes trays, hangers or other fitments (101 ) move around the path.

22. A chain system according to any one of claims 1 8 to 20 characterised in that a pair of chain systems formed from triangular links (1 12) are overlaid but parallel displaced, the apices of each of the triangular links (1 12) having a pivot (1 1 5) and being interlinked to the adjacent link ( 1 1 5) of the other chain system by a crank (1 16) of equal length to the parallel displacement of the two chain systems, the pallets, storage boxes trays, hangers or other fitments (101 ) being attached to the cranks (1 16).

23. A chain system substantially as disclosed herein, with reference to, and as shown in figures 1 to 10 of the accompanying drawings.

24. A conveyer system utilising a chain system as claimed in any one of claims 1 to 23.

25. A storage system utilising a chain system as claimed in any one of claims 1 to 23.

Description:

Chain System

This patent application refers chain systems that comprise a number of similar shaped links which are joined by pivots sequentially to form a loop or endless chain. Such chain systems might be used for transporting material or people and might also be used for manufacturing production line or storage system.

According to one aspect current invention a chain system comprises a chain formed from a series of six or more similar links that are connected for rotation about pivot points provided at the end of each link so as to form a continuous moveable loop, wherein the pitch ) of the chain is defined as the distance between the adjacent pivot points and is constant though out, characterised in that said chain is constrained such that the centre point of the links, being defined as the midpoint of the line joining the centre of the pivot points on the link , moves through a continuous closed defined path, wherein the path is specified as comprising two equal parallel straight sections and two equal semicircle sections, smoothly connecting the ends of the straight sections, so that the distance apart of the equal parallel straight sections equals the diameter of the semicircular sections and is equal to the pitch of the chain.

According to a preferred embodiment the length of the straight section of the defined path, which is also the distance between the centres of the two semicircular sections, is equal to the pitch of the chain multiplied by the number of links divided by two minus two times the pitch of the chain. So that where:

P = pitch of the chain

N = number of links

L = length of straight section of defined path (distance between centres of semicircular sections)

L = P. N/2 - 2P

According to a further preferred embodiment the guidance of the links to constrain the links to follow the defined closed path is achieved by guiding the pivot points of the links to follow two straight parallel channels, being set apart so the distance between the centre lines is equal to the pitch of the chain, having a length equal to the straight section plus the chain pitch, so that provided that the motion of the chain in the one channel is equal and opposite to the motion in the second channel then the motion of the links moving between the said channels, at the ends is defined the constrained adjacent links.

According to a further embodiment the links in adjacent channels are driven in opposite directions at the same speed by the provision of a sprocket centred midway between the channels and co-operating with abutments on the links to provide a positive conjugate drive. The sprocket teeth might be of involute form and might co-operate with a tooth form corresponding to a straight rack attached to the links. Alternatively the involute tooth form might co-operate with circular pins attached to the rack. A further alternative is to attach the pins to the pivot pins. Further, the sprocket might engage the chain at a point where increased accuracy of position is required.

The chain, described above, pivots only in one direction from being straight. A limit on the articulation might be incorporated into the design to allow the links to pivot in one direction only from the inline condition.

Many arrangements of Pallets or fitments might be made to the individual links to facilitate the design of conveyor systems for components, people or other use. When the chain is used in a horizontal arrangement, wheels

or bearings are required to support the moving load and reduce friction. In some arrangements it might be convenient to attach the pallets or fitments to alternate links. This concept might be extended to any such fitment that provides uniform spacing of the platens on the chain.

According to a further embodiment a pair of support links might be mounted for rotation, equidistant, between the channels to cooperate with an abutment pin at the centre point of the links, so that whilst the motion of the centre point of the links is circular during the transition from one straight channel to the other, the support links guide the abutment pin around a circular arc of diameter equal to the pitch of the chain. Each of the support links would be double ended so that as one end disengaged with one link the other end would be aligned with and engage with the next but one link.

An embodiment of the invention is now described, by way of example only, with reference to the accompanying drawings, in which:-

Figurei shows a single link of the chain;

Figure 2 shows a series of links joined together to form a length of chain;

Figure 3 shows the defined track for the pivots and the path for the centre point of the links;

Figure 4 shows the motion of the chain controlled by the straight channels through a sequence of positions;

Figure 5 shows the motion of the chain through a sequence of positions utilizing a linkage mechanism to control the centre of the links moving between the guidance channels;

Figure 6 shows a platen integral with the chain link;

Figure 7 shows a series of platens forming a length of chain; and

Figure 8 shows an involute drive gear engaging with pins attached to the chain assembly.

Figure 9a and 9b show the chain system with platens on alternate chain links.

Figure 10a, 10b and 10c shows an arrangement wherein the platens move about the prescribed track without rotation.

Figure 1 shows the important features of the link 10 constructed in accordance with the invention. The distance p between the link pin 1 1 and the pivot hole 12 defines the pitch of the chain. The link 10 has a central pivot 15 located midway between link pin 1 1 and pivot hole 1 2 at a distance q from the pivot hole so that:

q = p/2

The central pivot 1 5 does not protrude as far as the link pin 1 1 , as shown.

Figure 2 shows nine links 10joined to form a chain. The link pin 1 1 of the individual links 10 engages with the pivot hole 12 of the adjacent link 10.

Figure 3a shows the constrained path of the central pivot 1 5 for a closed chain system in accordance with the present invention. The path comprises two straight sections joined by semicircular end sections. The parallel distance apart of the straight sections and the diameter of the semicircular end sections is equal to the link pitch p. The distance L

between the centres of the semicircular end sections corresponds to an integer multiple of half of the link pitch p minus two times the link pitch:

L = p/2*N -2p

Where N is the number of links 10 in the chain.

Figure 3b shows the linear guidance path for the link pins 1 1 of the chain. The guidance path comprises two parallel offset lines of length M, where the offset is equal to p. The length M is equal to L + p so that:

M = p/2*N-p

For a practical guide rail to constrain the link pin to the prescribed path the guide rail needs to be offset by the radius of the link pin 1 1 .

Figure 4a - 4e shows the sequential movement of the chain around the prescribed path in accordance with the present invention. The upper figure of each of the positions shows a transparent view through the links 10 to demonstrate the interaction of the link pins 1 1 with the guide rails 30. The chain loop 50 is constrained by the guide rails 30 and the link pins 1 1 such that all but two of the link pins 1 1 are engaged and guided by the guide rails 30. The motion of the links 10 (also denoted 33 and 34 figure 4c) adjacent to the unguided link pin denoted 32 are determined by the position of individual link pins 35 and 36 in guide rails 30. provided that individual link pins 35 and 36 move equally in opposite directions then the motion of the centre of the links 33 and 34 will move in semicircular arc between the ends of the guide rails. The relative position of the chain loop 50 and the guide rails 30 is such that the end of the guide rails corresponds to the position of the link pins engaged with a link which is mutually perpendicular to its neighbouring links, as depicted in figure 4a.

The motion of the chain loop 50 can be seen by following the sequence of the figures from 4a to 4e as the chain loop 50 moves through a distance of one chain pitch p.

Figure 5 shows a means of positioning the chain loop 50 relative to the guide rails 30 (not shown figure 5). The position links 41 , 42, 43, 44 are mounted for rotation about their centre point at the centre of the semicircular path depicted in figure 3a. The length of the position links corresponds to the pitch p and the ends are formed into arcuate cups, where the distance between the centre of the arcuate cups is equal to the pitch p. There are two such position links (e.g. 41 , 42) at each end of the guide rails 30, as depicted left hand end of figure 5a. Position link 41 engages with the central pivots 45, 46 (also 1 5) on links 10 on alternate links as shown. The engagement of one end of the position link with the central pivot 46 occurs at the point of disengagement of the central pivot 45 ensuring that the alignment is maintained. Position links 43, 44 engage with central pivots 47,48,49 at the right hand end of figure 5a. The sequence of the motion of the chain 50 co-operating with the position links 41 , 42, 43, 44 is depicted in the figures from 5a to 5f as the chain loop 50 moves through one pitch p.

Figure 6 depicts four views of a platen 20 forming a link of the chain designed to support a vertical load for transport. The platen 20 has platen pin 23 corresponding to link pin 1 1 figure 1 , platen pivot hole 27 corresponding to pivot hole figure 1 and platen central hole corresponding to central pivot figure 1 . The platen pin 23 engages with the platen pivot hole 27 of the adjacent link in the chain. The platen 20 has support surface 27 which carries the load, and support rollers 22 acting on one edge of the platen 20 such that the bearing weight of an adjacent platen is taken by that edge of the platen directly through to the support rollers 22. The platen has drive discs 24 in the approximate location of the

platen pin 23 and the platen central hole 28. The distance between the drive discs 24 is equal to half the pitch p, and the offset from the platen pin 23and the platen central pivot 28 is equal and perpendicular to the line of centres. The drive discs engage with an involute gear 60 figure 8.

Figure 7 shows a view of a nine platens 20 joined to form a length of chain via the platen pins 23 and the platen pivot holes 27. Detail A shows how the load of one platen 20 is partly carried by the support rollers 22 of the adjacent platen 20.

Figure 8 shows a chain loop 50 constrained as previously described to move in the path depicted in figure 2. The six toothed involute gear wheel 60 engages with the drive discs 26 of the platen 20. For this number of teeth the circular pitch of the gear wheel 60 must equal the distance between the drive discs, being equal to half the chain pitch p. the lateral parallel distance apart of the two rows of drive discs must equal the base circle diameter of the gear wheel 60. The base circle circumference must equal the pitch of the drive discs times the number of teeth on the gear wheel 60:

Base circle circumference = p/2 * Number of teeth

In this case base circle circumference = 3p

The base circle diameter is 3p/pi

Where pi is equal to 3.142 approximately.

So that the parallel distance apart of the two rows of drive discs is approximately 0.955 times the chain pitch p. hence the slight eccentricity of the drive discs to the platen pin 23 and the platen central pivot 28. The detail B shows the gear wheel 60 engaging drive discs 62, 63 and

64. By mounting the drive discs 63 64 close to the platen pins 23 the path of the tips of the gear wheel 60 misses the platen pins 23 and allows a large addendum circle for the gear wheel 60. A second gear wheel 61 might also engage the drive discs 24 and have phase difference compared to the gear wheel 60. A force might be applied between the centres of gear wheel 60 and gear wheel 61 to put the chain in tension. Because the gear wheel 60 positions the chain loop in both guide rails 30, moving the links in an equal and opposite direction, the position of the chain is wholly defined.

Figure 9a and 9b show a chain system where the storage platens 101 are connected to alternate chain links 103 and move around linear guide 102. This allows the individual platens to double in length to twice the chain pitch. An interesting feature of the design is demonstrated by having the storage platens alternate, so the direction of access to the storage is varied as shown in the figure by the dotted hidden feature line 105.

Adjacent storage platens 101 close face to face or back to back. If there is a multiple of four storage platens 101 then the whole system can be closed for one position of the chain and open ended for the next position (as shown figure 9b). For this arrangement the storage system can be closed and sealed against weather, heat or cold, for one position of the chain storage system. For this position the chain system is in the general shape of a rectangular box.

Figure 10a, b and c depict an arrangement where the platens of a storage system move around the path described by the chain system without rotation. This might be used so that the contents of a box on the platens should not spill its contents in following the path of the chain system when that path is in a vertical plane. Figure 10a shows a chain system where the chain 1 12 has a triangular form to provide a pivot 1 1 5 away from the path of the chain. Figure 10b shows two such chain systems

overlaid but parallel displaced so that the corresponding pivots of the two chain systems engage with a crank 1 16 of length equal to the parallel displacement of the two chain systems. A platen 1 13 is attached to the crank and moves around the path prescribed without rotation. Figure 10c shows the motion of the platens unobscured by the linkage.

Various modifications might be made without departing from the invention. For example the guide rails might be slightly curved but remain substantially parallel, for example when configured as a travellator for carrying people the guide rails might follow the contours of the underlying surface over the arch of a bridge. Also, multiple gear wheels might be employed on a long chain, both to control the chain position and to provide drive motion. Different numbers of teeth might be used on the gear wheel provided that the drive disc numbers and location are also adjusted. The mechanism might be employed in transportation. For example a storage system could be fitted on a goods vehicle enabling better access to the transported goods. The system might also be employed as part of a tool changing system on a machine.




 
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