irst of Advance range from Primrose
Page 31
If you've noticed an error in this article please click here to report it so we can fix it.
The first model of the new Primrose range trailers, the Advance range, is a 40ft I-purpose, container-carrying flat, with a ton wide-spread tandem bogie having a -tracking rear axle. The first one has gone service with W. H. Bowker and Sons , haulier, Blackburn.
in the prototype, both axles were selfking, but as finally offered in standard 7, just the rearmost axle is self-tracking.
i gives enough improvement in ioeuvrability for most operators' pura,s, since the cut-in of the trailer is five to only the distance from the 1-pin to the leading axle of the bogie.
he self-tracking axle is made under licence Ceschi of Italy. In its 10-ton form, transverse damping of the stub axles is given by an air bellows horizontally disposed between the track rod and the axle beam. On the single-tyres 6-ton axle this damping (to prevent wheel flutter) is done by telescopic hydraulic units.
The load-rating of each axle depends on the tyre equipment. With 10.00-20, 14-ply tyres the axle rating is 9; tons: with 10.00-20, 16-ply tyres it is 10 tons, allowing a full 20-ton bogie at the 7ft lin. spread. A self-tracking axle is not mandatory with a Primrose wide-spread bogie. The rigid version of the Primrose wide-spread bogie saves £245 in list price.
Two basic 40ft trailers are available. They have the same 10ft 8in. rear overhang to centre line of bogie, the spread of which is 7ft lin. One model is rated at 28 tons gross and is for operation at 32 tons gross combination weight. The other is for future operation at up to 38 tons gross combination weight and is itself rated at 31 tons gross. The 32-ton g.c.w. trailer is 27ft from king-pin to centre line of bogie and has a front overhang of 2ft 4in. The 38-ton g.c.w. trailer is 26ft 10in. from king-pin to bogie centre-line and has a front overhang of 2ft 6in.
On the lighter model the standard brakes are 16+in. diameter and 7in, wide, with 8 in.wide brakes as an option. On the 38-ton model the 8in. brakes are standard. A load-compensating valve in the braking system is standard.
For each model the chassis frame is the same, consisting • of 20m-deep fabricated l-section side beams, having lin.-thick webs and ;in.-thick flanges, braced by 8in. sided box-section cross-members as well as upper 4in. by 11in. threaded full-width crossbearers. The neck section is 10in.-deep. Twospeed landing legs are standard.
The suspension of the wide-spread bogie is supplied by Rubery Owen Rockwell. The springs, spring brackets and radius rods are interchangeable with those of close-coupled bogies. Single-leaf springs are available as an option to save weight.
Each 40ft trailer is available in four forms; as a chassis, as a plain platform, as a skeletal or as a boarded skeletal for dual-purpose work. This last one is the dearest model; the list price of the 32-ton is £2,535. and of the 38-ton £2,680.