One jump ahead of the jumbo jets
Page 36
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PUSH-BUTTON POSITIONING OF AIRSIDE VEHICLES by Derek Moses
• Two new Hi-Lift vehicles have been developed in readiness for the introduction of Boeing 747 Jumbo Jet aircraft on international routes next year. The new aircraft will carry between 366 and 490 passengers.
One is a Commer Maxiload 2141in.wheelbase machine with bodywork by Oswald Tillotson Ltd. of Burnley and the other a Bedford KML 208in.-wheelbase chassis with bodywork by Caddey (Coachbuilders) Ltd., Addlestone, Surrey. Both incorporate new equipment designed by Edbro Ltd., Bolton, Lancs.
The new feature is an hydraulic pushbutton mechanism which can move the body forward when it has reached a height of about one foot greater than that of the driver's cab. This means that the body can be positioned automatically right up against an aircraft hatch, dispensing with the need for loading bridges and providing allweather protection for both loading staff and cargo.
On the Commer the body can move 6ft 4+in. forward of its normal position and on the Bedford the movable distance is 7ft 34in. In both cases the body is mounted on an Edbro reinforced steel subframe fitted on each side with traversing channels and rollers. The horizontal movement is effected by a double-acting hydraulic ram fitted within the sub-frame.
The controls for both the forward and return action are provided inside the body. The interlocking safety system which prevents forward movement of the body until it is well clear of the top of the driver's cab also acts in reverse so that the body cannot be fully lowered until it has been returned horizontally to its normal fixed position.
To meet the needs of larger aircraft, the Edbro scissors mechanism can raise the body to a height of 18ft from the ground, depending on the type of chassis used.
Another development from Caddey is a new Craftsman stairway mounted on a Ford D200 120in.-wheelbase chassis/cab. On this model the maximum platform height has been considerably increased. It may be elevated from a minimum height of 10ft up to a maximum of 15ft.
To provide additional clearance on the platform for the aircraft door, a sliding door is provided to each side of the top of the stairway. The wide stairway has a minimum width of 3ft and all treads and risers remain at a constant angle regardless of platform height.