Welding Aluminium Cuts
Page 55
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Body Weight by 25°/0 New Welding Method Exploited in Construction of Light-alloy Tipping Bodies of 5-7-ca.-yd. Capacity ALTHOUGH the application of gas welding to the construction of light-alloy commercial-vehicle bodies dates from the early 1930s, production difficulties have been a deterrent to its general adoption by bodybuilders. When, some 18 months ago, the Syntilla Manufacturing Co., Ltd., Dunstable, started to build a range of light-alloy tipping bodies with the trade 'name of Weldalloy, they were able to employ a new welding method which greatly facilitated construction. This is the consumable-electrode, argon-shielded, arc-welding process.
The Weldalloy range now comprises 5-, 6 and 7-cu.-yd. types. Weight is reduced by about a quarter, by obviating the use of bolts and rivets, and the saving in comparison with an all-steel body is more than 60 per cent.
Weldalloy bodies are designed by Lorry Bodies (LutOn and Dunstable), Ltd., Luton Road, Dunstable, Who have, so far, specialized in types for Bedford chassis. These are marketed through the Vauxhall dealer organization. The latest type to be developed is the 5 cu. yd., which has a slightly different form of construction from the others.
Net body weights are 41 cwt. (5 cu. yd.), 5 cwt. (6 cu. yd.) and 51 cwt. (7 cu. yd.). Including the Edbro 2LN front-of-body tipping • gear, timber blocks and rear wings, the 5-cu.-yd. body weighs 7 cwt. A Bedford oilengincd short-wheelbase chassis with the Weldalloy body weighs 2 tons 131 cwt. and the petrol-engined version 2 tons.
Side .extensions are available, which, although fully reinforced, are comparablf light. Extensions for a 6-cu.-yd. body, which increase the capacity by 1 cu. yd., weigh only 50 lb. Bodies for carrying cement are available with modified tailboard hinges mounted behind the corner posts and fitted with rubber scaling strip. There are no " seams, so that the body is dustproof.
The body is similar in form to the conventional welded-steel type, but is built as a flexible structure to provide even distribution of shock loads and so on. The alloys employed are 13.A.27 and B.A.M./27, and were originally developed for marine work. They are highly resistant to corrosion, as well as being suitable for the particular welding process employed.
Welding is performed with a QuasiArc Sigma unit, which gives a continuous weld requiring no cleaning or after treatment, The joints are physically stronger than the surrounding metal The unit operates on the continuous feed principle and it is possible to weld at rates up to 36 in. a minute. This facility enables the body to be marketed at £210 to £230, according to capacity. The robust underframe is constructed of 1-in. plate folded to form channelsection main members and of 3/16-in.
cross bearers of similar material and section, the three parts of each bearer being welded to the longi tudinals. The ends are also welded to the folded-channel side-reinforcing members.
The one-piece floor is Ain. thick and forms lap joints with the one-piece sides of 1-in. material, which provide bevelled corner sections. Double folds in the side sheets give integral top stiffening. The underframe is built up of prefabri cated welded sections. • Individual features of the 5-cu.-yd. body include a full-width angle crossmember at the front, additional angle stiffeners between the cross-members and a recessed ram casing which acts as a stiffener and obviates the necessity of upright reinforcing members. All the bodies arc fitted with gusset plates welded between the cross-members and fongitudinals to give lateral stability when cornering and travelling at a steep angle on rough ground.
The 5-cu.-yd. body is 8 ft. long inside, 6 ft. 11 in. wide and 2 ft. 71 in. deep. The larger bodies are 10 ft. long and 5 ft. 11 in wide, arid heights vary from 2 ft. 5 in. to 2 ft. 9 in.
The body is jig-built throughout, and the various sections are initially assembled by tack welding, so that distortion can be rectified before final welding. It is claimed that the form of construction employed, and the use of a thick stressed floor and side plates, give threefold resistance to buckling by shock loading. This is attributed partly to the elasticity of the structure.
Light-alloy platform bodies and other types could be produced by this process. An extension of existing production facilities will enable the concern's bodybuilding work soon to be expanded.
The metal rectifier of the Sigma unit is housed in a wheeled cabinet, and the 'equipment is readily moved to any work position. The welding gun is water cooled, but is of light weight.
All the light-alloy materials are supplied by the British Aluminium Co., Ltd.