GB2228911A

GB2228911A - Increasing the spacing between receptacles of an endless conveyor

Info

Publication number: GB2228911A
Application number: GB9005145A
Authority: GB
Inventors: John Briggs Holt
Original assignee: National Research Development Corp UK
Current assignee: National Research Development Corp UK
Priority date: 1989-03-08
Filing date: 1990-03-07
Publication date: 1990-09-12
Also published as: GB9005145D0

Abstract

A conveyor assembly 10 (Figure 3) is operative to convey a group of items from a first location 41, at which the assembly presents receptacles with a first receptacle-to-receptacle spacing, to a second location 45 at which the assembly presents stationary receptacles having an increased second receptacle-to-receptacle spacing. The receptacles may move continuously or intermittently past the first location. The increased spacing may be achieved by flexible elements between the receptacles or by means of chain links with slotted connections to allow relative movement in the longitudinal direction of the chain. <IMAGE>

Description

CONVEYOR ASSEMBLY The present invention relates to a conveyor assembly incorporating an endless conveyor.

The invention also relates in particular, but not exclusively, to an automatic planter or transplanter incorporating such an assembly.

According to the present invention, there is provided a conveyor assembly comprising an endless conveyor for conveying a group of items from a first location at which the assembly presents receptacles with a first receptacle-to-receptacle spacing to a second location at which the assembly presents stationery receptacles having an increased second receptacle-to-receptacle spacing.

When at the first location, the spaced-apart receptacles can either be stationary or moving. They might be stationary, for example, where the assembly comprises part of an automatic module planter or transplanter for moving plants which have been grown in compost in cells in a tray from a first location at which they are ejected from the tray, to a second location at which they are mechanically placed in plant pots for filling, as required, with addiftional compost. On the other hand, they might be moving, for example, where the assembly comprises part of an automatic planter or transplanter for the transfer of cuttings or bare-rooted plants in a medium to plant pots for mechanical potting.

Conveniently, the conveyor comprises a roller chain in which the rollers are mounted on element-connecting members, and the elements are slotted (i.e. provided with long apertures or "slots") so as, in appropriate situations, to allow relative motion to occur between the elements to provide the different receptacle-to-receptacle spacings at the first and second locations.

In an alternative arrangement, adjacent elements of the conveyor are connected by flexible members which allow relative motion to occur between the elements to provide the different receptacle-to-receptacle spacings at the first and second locations.

Conveniently, the assembly includes drive means operative to move the receptacles intermittently past the first and second locations.

Alternatively, the assembly includes drive means operative to move the receptacles continuously past the first and second locations.

In one arrangement, the assembly includes drive means operative to move the receptacles continuously past the first location and the relative motion between the elements is used to provide groups of stationary receptacles at the second-location.

Conveniently, in this latter case, the drive means comprises an accelerator drive which periodically operates to hurry the receptacles into their desired stationary positions at-the second location.

Conveniently, the accelerator drive is operative to move the receptacles at about twice their previous speed.

In an alternative arrangement, the assembly includes drive means operative to move the receptacles intermittently past the firstWlocation and relative motion between the elements is used to provide groups of stationary receptacles at the second location.

Conveniently, a removable stop is provided at the downstream end of the first and/or second locations.

Conveniently, the assembly includes means for loading and unloading the receptacles at the two locations.

The invention also includes an automatic planter or transplanter utilising the conveyor assembly of the present invention.

In one such embodiment, the planter or transplanter also includes loading means which are operative to load receptacles at the first location with a row of plants from a module carrier and discharge means for unloading the receptacles at the second location e.g. into plant pots.

In another such embodiment, the planter or transplanter includes means whereby cuttings or bare-rooted plants can be loaded into the receptacles at the first location so as to be positioned e.g. automatically, in plant pots at the second location for mechanical potting.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying, somewhat diagrammatic, drawings in which: Figures la,lb and ic are respectively plan, side and end views of part of a conveyor assembly according to a first embodiment of the invention, while Figure ld is a side view of one of the elements used in the assembly; Figures 2a and 2b are plan and side views of a conveyor assembly according to an alternative embodiment of the invention; Figure 3 shows, in diagrammatic form, a side view of another conveyor assembly illustrating different stages of its operation; Figure 4 shows, in diagrammatic form, a side view of a further conveyor assembly illustrating different stages of its operation;; Figure 5a and 5b are end views of two designs of plantgripping unit for use In a conveyor assembly; and Figure 6 is a side view of a conveyor assembly showing a different mode of operation to that illustrated in Figure 4.

Where convenient, the same reference numerals have been used to indicate structurally and/or functionally similar or identical items or parts of items In the different embodiments illustrated.

Referring first to Figures la,lb and lc of the drawings, these show a variable-pitch chain conveyor assembly 10 in both its closed up state (at 12) and its extended state (at 13).

For convenience In construction, the side plate elements 15 of the chain are formed with tabs 17 and 18 which are spot welded together. To these, are attached appropriate plant grippers or carriers (not shown). Chain pins 20 are fitted with rollers 22 (or other suitable elements) for guiding the chain in a track 23.

Figure ld shows the elements 15 to have a circular hole 24 for accommodating the associated chain pin 20 and a slot 25 for accommodating the chain pin of the adjacent pair of elements.

The ratio of extended to closed pitch with this arrangement is somewhat limited. Typical figures would be 84mm extended pitch and 50mm closed pitch.

To allow a higher pitch ratio, the alternative form of conveyor illustrated in Figures 2a and 2b may be preferable.

These figures show a conveyor assembly in which sliding chain elements 26 are linked together by a chain 28 or other flexible elements 30 (Figure 2b). This link enables the sliding elements 26 to be pushed together as at 32 or drawn apart as at 33, larger ratios of extended to closed pitch thereby being obtained.

Apertures 35 in the elements 26 are provided for the engagement of the teeth on drive sprockets 37, 38 (Figure 3) which are driven at the same speed as one another but intermittently. In other embodiments (not shown), the drive sprockets engage instead with the trailing edges of the elements 26 or with suitable protruberances provided for this purpose.

Jhe modules are grown in trays containing an array of, for example, 24 x 12 cells, and in order to receive the ejected modules the chain elements 26 must be at the same pitch spacing as the tray cells, for example 28mm, and stationary during the transfer. They must then be moved to the potting facility while being spaced out to suit the pitch spacing of a row of pots, for example lOOmm, and be stationary during the potting process.

This application of the assembly is illustrated in Figure 3 where reference numeral 39 indicates a module tray at a first location 41 where the plant carriers are closely spaced and reference numeral 43 indicates a row of pots at a second location 45 where the conveyor-mounted plant carriers are spaced to suit the pot spacing.

If the number of cells in the tray row is the same as the number of pots, both plant transfer and potting will occur at each dwell period in the conveyor drives but if, for example, there were 24 cells in a row and only 8 pots, then a row of modules would be ejected at every third move of the conveyor. In both these cases, sprocket 38 need not be driven.

If the ratio of cells and pots is not a whole number, the run and dwell periods of sprockets 37 and 38 must differ, and therefore both must be driven, and a buffer section of conveyor, where chain elements can be at variable pitch spacings during the cycles, is required between locations 41 and 45 and between sprockets 37 and 38 (at zone 50). A movable stop 52 may be provided to ensure the accurate positioning of the module carriers during the transfer operation.

Turning now to Figure 4, this shows a particular application of a conveyor assembly according to the present invention in which cuttings or bare-rooted plants are moved from a first location 60 where they are placed by an operator in carriers (not shown) attached to the chain elements 26, to a second location 62 where they are positioned in plant pots 64 for mechanical potting.

In operation, the sprocket 37 is driven continuously in the direction indicated while the sprocket 38 is driven intermittently at a suitably higher speed e.g. at double the speed of sprocket 37. When sprocket 38 Is driven, the chain elements 26 bunch up close together at location 59. During the periods when sprocket 38 is stationary, however, the chain elements 26 will bunch up instead at location 60. During these latter periods, the chain elements 26 at location 62 are stationary and at a pitch spacing to suit the row of plant pots 64, thereby enabling the mechanical potting process to take place. A buffer zone at location 66 may be provided between locations 62 and 64 if required.

When sprocket 38 is next driven, the chain elements 26 positioned as above described at location 62, are drawn from this location. At the same time an equal number of elements are drawn from the combined locations 60 and 66.

The potting mechanism, not shown, includes compost delivery chutes, a vibrating or tamping unit and a handling system for empty and full pots.

Important benefits of this utilisatlon of the conveyor assembly of the earlier Figures in the arrangement of Figure 4, are that the operator at location 60 has within easy reach a number of plant holders into which the plants may be placed and if a buffer zone is present at 66, the operator has time to obtain further supplies of plants without interrupting the potting operation. Typically the potting mechanism would deal with between 8 and 16 pots simultaneously.

Two possible arrangements of plant grippers 65 are shown in Figures 5a and Sb attached to the type of chain elements shown in Figures 2a and 2b and suitable for use in the layout illustrated in Figure 4.

In an alternative arrangement, shown in Figure 6, the chain conveyor passes round an idler sprocket 66 and a second sprocket 67 which is driven intermittently. During the dwell In the drive, the spaced out elements of the chain at location 69 are in the correct positions for the plants in their carriers to be planted in pots (not shown) while the stationary bunched-up carriers at location 71 can be loaded with plants by the operator. Because the carriers at location 71 are close together, the operator is able to load more than the number which are Immediately required for planting and therefore is able from time to time to obtain further supplies of plants. The difference between this arrangement and the previously described one is that the carriers passing through the operator's work area move intermittently instead of continuously.

It will be appreciated that an important feature of the illustrated embodiments is the variable pitch chain shown in Figures la,lb,lc and ld or the succession of elements linked together as in Figures 2a and 2b in such a way that when pushed together the elements are at a close pitch and when pulled apart the elements are at a wider pitch spacing. For convenience, both forms have been generally referred to as a "chain" since both may be driven by a form of sprocket. Carriers or grippers for the items to be conveyed may be attached to each element or to certain elements of the chain.

In some of the Figures, the conveyor assembly 10 has been depicted as running In a vertical plane but it will be appreciated that, with suitably arranged plant carriers or grippers, the chain could be arranged to run In the horizontal or in an Inclined plane.

Claims

1. A conveyor assembly comprising an endless conveyor for conveying a group of items from a first location at which the assembly presents receptacles with a first receptacle-toreceptacle spacing to a second location at which the assembly presents stationary receptacles having an increased second receptacle-to-receptacle spacing.

2. A conveyor assembly comprising an endless conveyor for conveying a group of items from a first location at which the assembly presents stationary receptacles with a first receptacleto-receptacle spacing to a second location at which the assembly presents stationary receptacles having an increased second receptacle-to-receptacle spacing.

3. A conveyor assembly comprising an endless conveyor for conveying a group of items from a first location at which the assembly presents moving receptacles with a first receptacle-toreceptacle spacing to a second location at which the assembly presents stationary receptacles having an increased second receptacle-to-receptacle spacing.

4. An assembly as claimed in any of Claims 1 to 3 in which the conveyor comprises a roller chain in which the rollers are mounted on element-connecting members, and the elements are slotted so as, in appropriate situations, to allow relative motion to occur between the elements to provide the different receptacle-to-receptacle spacings at the first and second locations.

S. An assembly as claimed in any of Claims 1 to 3 in which adjacent elements of the conveyor are connected by flexible members which allow relative motion to occur between the elements to provide the different receptacle-to-receptacle spacings at the first and second locations.

6. An assembly as claimed in any preceding claim including drive means operative to move the receptacles intermittently past the first and second locations.

7. An assembly as claimed in any of Claims 1 to 5 including drive means operative to move the receptacles continuously past the first location and the relative motion between the elements Is used to provide groups of stationary receptacles at the second location.

8. An assembly as claimed in Claim 7 in which the drive means comprises an accelerator drive which periodically operates to hurry the receptacles into their desired stationary positions at the second location.

9. An assembly as claimed in Claim 7 in which the accelerator drive is operative to move the receptacles at about twice their previous speed.

10. An assembly as claimed in any of Claims 1 to 5 including drive means operative to move the receptacles intermittently past the first location and relative motion between the elements is used to provide groups of stationary receptacles at the second location.

11. An assembly as claimed in any preceding claim in which a removable stop is provided at the downstream end of the first and/or second locations.

12. An assembly as claimed in any preceding claim including means for Joading and unloading the receptacles at the two locations.

13. A conveyor assembly as claimed in Claim 2 and substantially as hereinbefore described with reference to and/or as illustrated in the accompanying drawings.

14. A conveyor assembly as claimed in Claim 3 and substantially as hereinbefore described with reference to and/or as illustrated in the accompanying drawings.

15. An automatic planter or transplanter including a conveyor assembly as claimed in any preceding claim.

16. A planter or transplanter as claimed in Claim 15 comprising loading means which are operative to load receptacles at the first location with a row of plants from a module carrier and discharge means for unloading the receptacles at the second location.

17. A planter or transplanter as claimed in Claim 16 and substantially as hereinbefore described with reference to and/or as illustrated in the accompanying drawings.

18. A planter or transplanter as claimed in Claim 15 in which cuttings or bare-rooted plants can be loaded into the receptacles at the first location so as to be positioned in plant pots at the second location for mechanical potting.

19. A planter or transplanter as claimed in Claim 15 and substantially as hereinbefore described with reference to and/or as illustrated in the accompanying drawings.