Draftex Industries Limited

Rémi Boyen

Jacques Houis

Yann Lelievre

A flexible bellows, such as for protecting the end of a longitudinally movable steering rack, has a hollow connector mounted on it adjacent its larger diameter fixing collar. The connector enables a connection to be made from the interior of the bellows through a similar connector on a second bellows covering the opposite end of the rack and thus to the interior of the second bellows. As the rack moves to and fro, compressing one bellows and expanding the other, the increased pressure in the compressed bellows is automatically transferred to the expanded bellows. The connector is pre-produced, such as from relatively rigid material by a moulding operation, and then placed in the mould which is used for producing the bellows. A parison or preform of thermoplastics material is placed in the mould and then blown to form the bellows. This operation forces some of the blown material of the parison or preform into the open end of the connector, which at the same time secures the connector to the bellows and forms an opening through the wall of the bellows to connect the interior of the bellows to the interior of the connector.

Blow-molded articles and blow-molding methods for producing them

A protective bellows for protecting the steering mechanism of a motor vehicle body is shown. The bellows has a fixing collar for gripping the outside of the casing of the steering mechanism, and a fixing collar for gripping a mounting region of the steering rod. In order to be fitted into position, however, the fixing collar has to be stretched to pass over a boss of enlarged diameter. The bellows is produced by blow-moulding from EPDM-polypropylene or similar thermoplastic material. Because of the lesser resilience of this material, compared with previously used materials such as thermoplastic polyurethane, the initial diameter of the fixing collar has to be selected in dependence on the relative values for the diameters of the boss and the mounting region in order to ensure that the pressure with which the fixing collar grips the mounting region provides adequate sealing not only initially but throughout the expected life of the bellows.

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Nantes, France

Rémi Boyen