New Double-drive Bogie Produced by Kirkstall
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DESIGNED for maximum-load sixand eight-wheeled vehicles, arid for towing tractors-operating at up to 100,000 lb. gross train weight, a new bogie has been produced by Kirkstall Forge Engineering, Ltd., Leeds. It will be exhibited at the Commercial Motor Show at Earl's Court,"London. It is a doubledrive design with third differential, and incorporates new systems of mounting. suspension and gear reduction. To avoid any concentration of stress in the chassis, the bogie has a four-point mounting. This makes it possible to employ lighter frame members.
The width between spring centres is 3 ft for the top and 3 ft.
2 in. for the bottom, the frame width being 3 ft. 4 in. Other dimensions are: track, 5 ft. 1 lf in.; distance over hubs, 7 ft. 7+ in.: distance over the tyres after allowing for wheel offset, tolerance and tyre growth, 8 ft. The distance between the effective centres of the top springs is
3 ft. 4 in. and between the main bogie centres 4 ft. 6 in. The layout provides for the bogie being attached to the four frame brackets through the two secondary springs, which are located directly above the lower, or main, bogie springs. All four of these springs support the load. The lower springs are linked by a rectangular crossmember and articulate on needle-roller bearings.
There is a triple-gear reduction system, the first two stages being by helical spur gears and spiral bevels incorporated in the axle centre. The final stage is achieved by epicyclic gears which provide a 4: 1 reduction in each hub.
The overhead input design facilitates the provision of a straight-through drive to the rear of the twin axles. The differentials in the axles and hub are of restricted-action design so that traction is maintained under all road conditions.
Horizontally disposed radius arms resist the transfer of load from one axle to the other as a result of braking or driving action. The one piece forged axle casing has I-section arms.
The bogie is designed for use with 11.00-20 in. tyres. Brake dimensions are 151 in. by 7 in., the system having Clayton Dewandre diaphragm air actuators with a stroke of 21 in,