Transporter with link-type elevating gear
Page 49
If you've noticed an error in this article please click here to report it so we can fix it.
Al upper-deck elevating gear based on a link-type hydraulic system and overcapacity rams is a feature of a car transporter semi-trailer produced by Hoynor Ltd., Main Road, Danbury, Essex. The first production model was put into service last week in the fleet of transporters operated by Silcock and Coiling Ltd., Dagenham, Essex, following two months' successful use of the prototype by this company on routine delivery runs.
The prototype was designed over a weekend by Mr. G. Hoy, managing director of Hoynor, whose main objectives were simplicity and a long life, and the production model was ready for service on the stipulated date. Silcock and Coiling have contracted to purchase all the transporters manufactured by Hoynor for some time to come Hauled by a Ford D800 tractive unit having a 93 in. wheelbase, the trailer has an overall length of 42 ft. 6 in., which corresponds to the overall length of the outfit, the only non-standard feature of the unit being the use of Michelin X (900-20) tyres which are also fitted to the trailer wheels. The between-decks height is 5 ft. 7 in., which permits loading on the lower deck of standard 5 cwt. and 7 cwt. vans equipped with roof vents. Cars of all types can be carried on the transporter, the normal mixed load comprising four vehicles on the top deck and three on the lower deck. The payload of the trailer is about 12 tons.
The upper deck is hinge-mounted at the front on pivots (of the plain metal type with a diameter of 6 in.) in line with the king pin of the fifth wheel about 2 ft. above the coupling, which is located 1 ft. ahead of the axle. A car on the front section of the upper deck approximately balances the vehicle immediately behind it, which reduces the load on the lifting mechanism to two cars.
Two A utolifts single-stage 4.25 in. rams are located horizontally between the main chassis members spanning the axle and each has a capacity of 11 tons, the stroke being 27 in. Because the thrust of the rams is transmitted to a link mechanism, they are not subjected to side stresses, and in the raised position the load of the upper deck is supported by two steel locking pins of 1.25 in. dia. Low stressing of the rams and linkage should, it is anticipated, give maintenancefree service for an indefinite period apart from greasing of the bearings.
A robust cross tube ahead of the trailer axle carries extended bell-crank levers, the shorter arm of which receives the thrust transmitted by the rams, whilst the longer arms (on the outside of the main frames) are pivoted to vertical swinging links suspended from struts underslung from the upper deck. When the deck is in the lowered position the longer arms of the cranks and the links extend below the main frame members. Hydraulic power is supplied by a standard Autolifts p.t.o. driven pump designed for tipping vehicles.
Of all-welded construction the trailer is based on standard Rubery Owen pressedsteel 15 in. chassis members, whilst the standard 5 in. axle is produced by the same company. The cross-bearers of both decks are box-type members of 3 in. by 3 in. section, whilst the main members of the upper deck comprise 6 in. by 3 in. box sections. There are sloping sections at the rear of the lower deck (a 3 in. drop in 4 ft. and an 18 in. drop in 6 ft. 6 in.) that reduce the loading height to 2 ft. 3 in.
Having a length of 10 ft. two loading ramps can be used for loading either deck without re-positioning and are readily stowable on rollers under the chassis. A portable ladder can be suspended over the cab to facilitate operation of the front winches.
Expanded-metal wire-mesh is used for the flooring of both decks and is extended the full width of the vehicle (8 ft. 2 in.), to provide ample walk-ways for the loaders. The crossbearers of the lower deck pierce the main chassis members, the upper flanges of which stand 4 in. above the bearers and act as wheel guides, whilst the guides of the upper deck comprise Z-shaped members of 4 in. by 1 in. section.
Other details include twin-line air brakes and manually-operated landing legs. The control valves are duplicated and are located conveniently on the outside of the chassis in front of the rear axle. All the metal bearings of the linkage mechanism are of 6 in. dia.
P.A.C.B.
Conference for Managing Directors A TWO-DAY conference for managing directors and chief executives is to be held at the Grand Hotel, Eastbourne from noon, March 31 to noon, April 2. An established annual event, the theme this year is induStrial development, including staff and management training. Including accommodation and meals the fee is 52 gns. payable to the organizers, Industrial Administration Ltd., 18 Tbursloe Place, London SW7.