18120 - Rack transport system

The front-end module loading station is a rack transport system: it handles special transport pallets (racks) that receive finished front-end modules of passenger cars. We designed and built the system for an automotive plant producing modules for two passenger car models.

Intended use of the machine

The station is used to load front-end modules into racks. Each part must be placed on a specific rack and in a specific position. The station organises the loading process and sets the order in which the racks pass through the successive stations.

The station also creates a buffer of empty and full racks, so the line can run without interruption even when there are temporarily no parts to fill a rack or the forklift has not yet collected a full one.

Description of operation

The work cycle consists of the following steps:

  • the forklift operator places an empty rack on the infeed conveyor;
  • stop cylinders hold the rack until the first station is free;
  • once the stop is released, the rack rolls by gravity onto the first station, where it is locked mechanically. The operator unfolds the rack arms and loads the modules according to the loading pattern;
  • raising the rollers of the first station allows the rack to be moved to the second station. A mechanical pawl prevents the rack from rolling back, and a cylinder blocks entry onto the turntable while another rack is on it;
  • at the third station – the turntable – the rack can be rotated through 360°. Indexing positions every 180° give convenient access to both sides of the rack;
  • after the side rollers are raised, the full rack moves to the outfeed conveyor, where it is collected by a forklift.

Machine design

INFEED AND OUTFEED CONVEYORS

Gravity roller conveyors form a buffer of empty and full racks. Stop cylinders and a pull rod at the infeed make it possible to pull a rack in without stepping onto the station.

LOADING STATIONS

Two stations with lifting rollers are operated with UP/DOWN selector switches. Mechanical pawls prevent the racks from rolling back, and a safety cylinder controls passage to the next station.

TURNTABLE

The turntable rotates the rack through 360°. It has a locking cylinder and two indexing sockets every 180°; the lock is released with a push button on the control box. A green bumper marks the entry and exit position.

PNEUMATIC SYSTEM AND CONTROLS

All movements are pneumatic, so the machine needs no electrical power supply. The movements are controlled from two control boxes located at the stations. The air preparation unit has a manual shut-off valve, a pressure regulator and an automatic condensate drain.

TECHNICAL DATA

  • Supply: compressed air 0.5–0.6 MPa (min. Ø12 mm connection), no electrical supply
  • Dimensions (L × W × H): 5700 × 7000 × 2300 mm
  • Weight: approx. 400 kg

Safety level

A risk assessment was carried out for the station in accordance with EN ISO 12100. The safety switch on the control box shuts off and vents the air from the entire system, and restarting requires confirmation with the RESET button. The emergency stop complies with EN ISO 13850, and the safety functions are implemented in category B / PL b according to EN ISO 13849-1. Pinch points are guarded, edges are rounded, the pneumatic system complies with ISO 4414, and the machine is marked with warning pictograms.

Benefits for the customer/user

  • every module ends up on the right rack and in the right position;
  • a buffer of empty and full racks keeps the line running continuously;
  • the turntable allows ergonomic loading from both sides of the rack;
  • the fully pneumatic design without electrical supply means simple installation and low maintenance costs;
  • the forklift only drops off empty racks and collects full ones, reducing its time at the station.
Previous16239 - Stacja mieszania Poliolu