Slim-line powered trolleys enable Creation of versatile, narrow production line
7 Sep 2006
Utilisation of an Inductive Power Transfer (IPT) system by Excel Automation to deliver drive to individually powered trolleys that support cockpit assembly throughout a multi-station assembly line for the new Mini is believed to be a first in the
The new line installed at Intier Automotive Interiors for assembly of the Mini cockpit is a radical departure from the initial thinking of Intier project engineers which was to have a more conventional flow line with an overhead return for empty carriers, the latter to eliminate too much intrusion onto the floor area. Unfortunately plant height restrictions would not allow this style design.
During discussions with Excel Automation, its design team put forward the idea of using individually powered trolleys, channel guided throughout the process. Concern over excessive use of floor space was soon quashed since each trolley would be only 60cm wide.
Now fully operational, the system enables Intier Automotive Interiors to release one cockpit every 80 seconds for shipment to the main car production line.
Trolley Design
Each trolley supports a cockpit carcass between end clamps, and to facilitate the most convenient working position for component assembly at each of the 27 stations a large handwheel and associated simple pull brake-release has been incorporated allowing rotation of the whole cockpit.
At completion of each specific assembly process the operator presses a button and upon release of a 80 second tact time the trolley moves to the next station.
To bring flexibility to the whole assembly process Excel Automation chose to design each cockpit support in the form of a narrow, four-wheel trolley with free running castors at each corner to facilitate movements around bends. Guidance of each trolley is achieved by front and rear guide rollers, these run in a floor channel, guiding it through each of the 27 assembly stations prior to moving it to one of three electrical inspections stations. Any rejects move into a special remedial work area before re-entering the inspection stations. Diverter plates set within the floor channel control the flow of the trolley to a vacant test station.
After inspections approved cockpits route to a release station, here they are removed by a manipulator and loaded onto a shipping platen, which in-turn feed into a transfer and accumulation area where the platens are stored in sequence order prior to loading directly onto roll-on / roll-off lorries, all of this equipment was also designed and built by Excel Automation. Empty trolleys return automatically to a buffer area at the start of the assembly process to start the next build programme.
Success of the operation is attributed to the use of the IPT ® contactless inductive power transfer system that allows electrical energy to be supplied to cockpit trolleys without any electrical or mechanical contact.
Inductive Power
The IPT inductive power transfer system combines two parts, primary and secondary which are magnetically coupled, similar to a conventional transformer. The primary consists of a track power supply and track cable embedded in the floor and running either side of the guide channel. The pickups and pickup regulators (the secondary element), are mounted on the trolley frame. Unlike a conventional transformer, where primary and secondary are tightly coupled, the IPT is a loosely coupled system, and allows power to be transferred across 5mm air gaps due to the high operating frequency of 10 kHz to 25 kHz.
The adoption by Excel Automation of the IPT power drive system for this production line brought individual control and progress through the assembly process. Should a unit need to be removed from the line this is easily carried out by simply raising the drive assembly which is complete with guide rollers, without affecting progress of other trolleys.
The automated assembly line, designed and built by Excel Automation at its'
Commenting on the new line, Prawin Singh, Lead Project Engineer at Intier Automotive Interiors says, "Although the trolley concept for the new Mini cockpit production line was a radical departure from our initial thinking we are delighted with the solution Excel put forward, it has kept the whole process at ground level and brings added flexibility."
The Docking Station
Cockpits released for delivery from the production line are placed on an Excelvayor power roller accumulation conveyor and move to a transfer station comprising turntable, powered roller section and scissor lift. It accepts individual cockpits, rotating them through 90 degrees ready for entry into a two- tiered powered roller accumulation rack. Strategically positioned sensors enable the monitoring of the number of cockpits passing into the lower deck.
When the prescribe number, 15 in the case of the Mini cockpit, have accumulated in the lower level, each new cockpit arriving on the turntable is raised by scissor lift and simultaneously turned through 90 degrees, before being released to the upper deck. When full, the cockpits await final transfer to a vehicle's trailer ready for JITdespatch to the main plant.
Each vehicle trailer has been fitted out by Excel with a two-tier roller conveyor arrangement mirroring that of the holding bay. As a trailer moves into the docking station a series of traffic lights provide indication to the driver and a levelling system ensure that the trailer is aligned with the of board conveyors. The driver then triggers via a push button the loading sequence and release of cockpits. The transfer sequence means that the last unit to enter the holding bay is first into the trailer. At the main car production plant the first cockpit to be automatically released is the first that entered the holding bay at the cockpit build plant.
The Intier Automotive Interiors installation highlights how, given a design brief Excel Automation looks for the most advantageous solution for its client, not necessarily following conventional guidelines.
Sales enquiries:
Kevin Staines
Excel Automation Ltd
Gregory's Bank
Tel: 01905 721500
Fax: 01905 613024
Email: kevin.staines@excel-automation.co.uk
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