More strength less weight from special sills in new Barham tippers
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• All the main load-carrying sections in a new range of welded semi-trailer tippers introduced by Barham Bodies Ltd are aluminium extrusions. Thus, it is claimed, strength is provided in the extruded sections where it is needed—with no surplus weight. They have been specially developed for use in fixed-side tippers by Alcan Booth Industries Ltd, supplier of all the aluminium material in the new bodies.
Full advantage is taken of the inherent beam strength in the body sides, which does away with the need for underfloor runners. The bottom sill, which provides the tensile strength in each body side "beam", is an entirely new intricately-shaped Alcan section. It incorporates a 2.5in. by 45deg corner flange, which not only resists racking stresses but assists in achieving a clean discharge of clinging loads. Weaknesses arising from welded joints in the sill are avoided by the use of one-piece extrusions along the full length of the body. Overall depth of the extruded bottom sill section is 8.9in.; the boxed rail portion is 3.4in deep. The same section is used along the base of the front bulkhead, with a 45deg-mitred joint at each corner.
Full-width 3in. by 3in. extruded channel-section underfloor crossmembers are employed. A robust joint between floor and sides is ensured by recessing and welding the ends of the crossmembers into the boxed rail section of the sill extrusions.
Shock loadings on the 0.25 in.-thick floor are resisted by spacing the floor crossmembers 15in. apart. Side posts of the same 3in. square channel section are pitched at 25in. intervals.
A rectangular box-section extrusion 4in. deep and 3.2in. wide makes up the full-length top rail on each side. It incorporates a stiffening rib on its outer face to minimize impact damage from loading shovels and so on.
Strength at each front corner of the body comes from a top-hat section connecting the adjacent side and bulkhead posts. At the rear a heavy-duty aluminium angle provides mounting positions for alternative tailboard fittings. Whilst the normal tailboard is the one-piece top-hung type, other arrangements are available to suit individual applications.
Body lengths from 28 to 32ft are offered by Barham. Because of the built-in beam strength of the sides, the minimum body height available is 2ft. Standard width is 8ft 2in., overall, corresponding to a 7ft Sin. interior dimension.
By dispensing with body runners, the floor level is reduced to only 3.7in. above the top of the trailer main frame.
Any tipping semi-trailer frame, it is said, can take the new Barham bodies, which are being built in a section of the company's Northampton works now allocated to welded and tipper construction.
The first of the new units to be completed was supplied to George Varney and Sons Ltd, of Silverstone, Northants. It is a 30-footer on a Crane Fruehauf DB30F2E chassis, plated at 27 tons gross trailer weight. It is equipped with Edbro 7CAN twin-ram, five-stage gear giving a 38deg angle of tip. Unladen weight of the complete trailer is just 5 tons. The tipping gear is mounted ahead of the fiat-fronted body. Where absolute capacity or weight distribution is critical, or where a single-ram gear is specified, this can be fitted—recessed into a "pocket" in the headboard.