GB2161776A

GB2161776A - A conveyor system for feeding work stations

Info

Publication number: GB2161776A
Application number: GB08417711A
Authority: GB
Inventors: John Sheader; Kevin John Davies
Original assignee: British Nuclear Fuels PLC
Current assignee: Sellafield Ltd
Priority date: 1984-07-11
Filing date: 1984-07-11
Publication date: 1986-01-22
Also published as: GB2161776B; BE902848A; IT8553589V0; DE3524672A1; IT1182505B; GB8417711D0; FR2567495B1; JPS6144398A; IT8567638A0; FR2567495A1

Abstract

A conveyor system comprises carriages (15-17) drive, e.g. by a linear motor, a prearranged sequence of steps to move workpieces in forward and reverse directions between work stations. Each work station has a park position and a work position and each carriage has a number of compartments for workpieces spaced apart at a pitch equal to the spacing between the park and work positions at each station. Transfer means at the work stations move workpieces between the carriage compartments and the park and work positions. The workpieces can be nuclear fuel pins mounted in carriers and the carriages shuttle to and fro between adjacent stations to move fuel pins and carriers in a forward direction and the return empty carriers in a reverse direction. <IMAGE>

Description

SPECIFICATION An improved conveyor system The present invention concerns a conveyor system for transporting workpieces between work stations.

According to the present invention a conveyor system comprises drive means having carriages movable together in a pre-arranged sequence of steps to move articles in forward and reverse directions between work stations and means at the work stations for transferring the articles between the carriages and the work stations.

The conveyor systems can be used for the transport of nuclear fuel elements between work stations at which different work operations are performed on the fuel elements. The fuel elements can be nuclear fuel pins mounted in carriers. The system progressively moves pins and carriers from station to station in a forward direction and returns empty carriers in the reverse direction.

The invention will be described further, by way of example, with reference to the accompanying drawings; in which: Figure 1 is a schematic illustration of an embodiment of a conveyor system; Figure 2 is a diagram of a sequence of operations.

A conveyor system utilises a single linear motor having a stator which is divided into individual sections. A work station is associated with each section and the system includes carriages which are driven by the motor to shuttle to and fro between adjacent stations in a predetermined sequence of movements. Three work stations appear in Figure 1, the associated motor sections being denoted by reference numerals 12, 13 and 14 and the carriages by reference numerals 15, 16 and 17.

The conveyor systems transports workpieces mounted in carriers in one direction and returns empty carriers in the opposite direction. The workpieces can be nuclear fuel pins which are subjected to various work operations at the different work stations. In Figure 1, fuel pins mounted in carriers are moved from left to right and empty carriers are moved from right to left.

Each carriage is provided with three equally pitched compartments. Each work station includes a park position and a work position with means at each of the positions to transfer workpieces and carriers between the carriages and the work stations. Thus, a transfer mechanism at each work position can transfer a fuel pin and its carrier into and out of a carriage compartment located at the work position. A second transfer mechanism is associated with each park position for transfer to and from a carriage compartment located at the park position. The distance between the two transfer mechanisms at each work station is equal to the pitch of the compartments in the carriages.

Figure 2 shows a sequence of operations in transporting fuel pins located in their carriers from the start of a production facility at a Pin Entry Station, through work station 1, 2 and 3 to a Pin Exit Station at which the pins are removed from the carriers an the empty carriers are located in the carriages for return to the pin entry station to receive fresh fuel pins.

Initially a fuel pin mounted in its carrier is located in both the park and workstation positions at each of the stations 1, 2 and 3. Also a fuel pin attached in its carrier is located in the pin entry station and an empty carrier is located in the pin exit station. An empty carrier is located in the left hand compartment of each carriage. The fuel pins mounted in carriers are denoted by the capital letter A, B, C, D, E, F, G and empty carriers by the lower case letters a, b, c, d, e.

The sequence of operations is as follows.

1. The fuel pin A, in the pin entry station is located in the centre compartment of the first carriage.

Fuel pins B, D, and F in the park stations 1, 2 and 3 are located in the centre compartments of the remaining carriages. Also fuel pin C, E, and G in the workstations 1, 2 and 3 are located in right hand compartments of the remaining carriages. All the previously described operations happen simultaneously.

2. The carriages are indexed by the linear motor one compartment pitch to the right.

3. The pins B, D and F in the centre compartments of the carriages are transferred into the vacant work positions at stations 1, 2 and 3. Also simultaneously empty carriers a , b, c and d in the left hand compartment are transferred into the pin entry and park positions at the respective stations.

4. The carriages are moved to the right through one section of the conveyor system to bring the empty left hand compartments of the carriages opposite the park position and pin exit position at the respective stations.

5. The empty carrier b , c, d and e at park stations 1, 2 and 3 and pin exit station are loaded into the left hand compartments of the carriages.

6. The extreme left hand carriage is indexed one compartment pitch to the left. All other carriage are indexed two compartment pitches.

7. The fuel pin A in the centre compartment of the extreme left hand carriage and fuel pins C, E and G in the right hand compartment of the remaining carriages are transferred to the park and pin exit positions at the respective positions.

8. The carriages are indexed to the left through one section of the conveyor system to bring the middle compartment opposite the pin entry and park positions at the respective stations.

The system has now returned to a condition conforming to its initial position. A fresh fuel pin is introduced into carrier a and the assembly becomes H and a completed fuel pin is removed from G the carrier becoming f.

It can be seen that all the fuel pins have been moved to the right through one section of the system and all carriers have been moved one section to the left. As can be seen from Figure 2, the only intrustion into process time occurs during steps 1, 2 and 3 of the sequence, these being respectively the loading of a pin into the carriage at its respective work station, indexing the carriage one pitch to the right and loading the next fuel pin from the carriage int its work station. All the other steps in the sequence occur during the time taken to perform operations at the work positions at the stations. The speed of the linear motor can be arranged that steps 4 to 8 in the sequence are completed during the process time such that the overall time for the complete sequence is kept to a minimum.

It will be appreciated that the above arrangement is but one example of a conveyor system according to the invention for moving workpieces in one direction through successive work stations and returning carriers for the workpieces in the opposite direction. The system can be modified and adapted to serve any desired number of work stations. The drive means need not necessarily be a linear motor. For example, a mechanical or pneumatic drive can be provided. The arrangement eliminates a loop return track of a conventional conveyor.

Claims

1. A conveyor system comprising drive means having carriages movable together in a pre-arranged sequence of steps to move workpieces in forward and reverse directions between work stations and means at the work stations for transferring the workpieces between the carriages and the work stations.

2. A conveyor system comprising a plurality of work stations including an entry station and an exit station, a park position and a work position at each work station, a plurality of carriages associated with the stations, each carriage having a plurality of compartments to receive workpieces, drive means for shuttling the carriages to and fro between adjacent stations and transfer means at the park and work positions to transfer workpieces between the carriages and the workstations.

3. A conveyor system according to Claim 2 in which the carriage compartments are spaced apart at a pitch which is equal to the spacing between the work and park positions at each work station.

4. A conveyor system according to Claim 2 or 3 in which the drive means comprises a linear motor divided into individual sections with a work station associated with each section.

5. A conveyor system according to any preceding claim in which the workpieces comprise nuclear fuel pins mounted in carriers, the fuel pins and carriers being progressively moved from station to station in a forward direction and empty carriers being progressively moved in the reverse direction.

6. A conveyor system for transporting workpieces between work stations substantially as herein described with reference to and as illustrated in the accompanying drawings.