Taskers Semi-trailers Lose Weight
Page 51
If you've noticed an error in this article please click here to report it so we can fix it.
TWO new semi-trailers to be shown by I Taskers of Andover (1932), Ltd., at the Commercial Motor Show are markedly lighter than previous comparable models. The 15-ton Twinside semitrailer, with side-by-side twin axles, weighs 2 tons 15 cwt. complete with a 25-ft. hardwood platform body.; whereas the earlier Taskers model with this bogie weighed 3 tons 19 cwt.
A tandem-axled bogie with single wheels and tyres on the rear axle has been. developed for the Tandem Six 16-ton semi-trailer, and this makes a substantial contribution to its low unladen weight of 3 tons 24 ,cwt. It is also cheaper than conventional tandem-axle types.
The Tandem Six bogie has tubular axles. The forward beam is 5 in. in diameter and carries twin Michelin D.20 X tyres and 154-in.-diameter brake drums with 6-in.-wide linings. Single tyres of the same size are fitted to the trailing axle which is 4+ in. in diameter and has 154-in. diameter brake drums with 34-in.-wide linings.
The rear wheels are on the centre line of the forward pairs so that the effective track for both axles is. the same. The brakes are Girling two-leading-shoe units with twin-line air-pressure operation.
Unequally pivoted balance beams link the leaf springs at each side of the fourSpring bogie. This distributes the load in the ratio of 2 to 1 over the front and rear axles. A lever-type shock absorber is fitted between the rear section of each balance beam and the chassis frame. This is designed to reduce axle hop on braking and to damp out periodic oscillations.
The Tandem Six semi-trailer has a pressed-steel welded chassis frame with box-section cross-members. With a 14-in,thick hardwood floor, it is more than 10 cwt. lighter than other Tasker tandemaxle types having a similar basic specification.
A rolled-steel frame with 7 in. by 3 in. longitudinals and angle-section under
bracing is employed for the Twinside 15-ton straight-frame model. It is in the construction of the welded frame that the majority of weight reduction has been achieved.
The twin-axled bogie is a type used before by Taskers and has single leaf springs clamped to each square-section axle. The spring ends locate in split rubber bushes, which absorb axle oscillation, and abut against rubber-cushioned steel end plates which restrict fore-and. aft movement.
Each wheel carries a 154-in.-diameter brake drum with 44-in.-wide linings operated mechanically by a two-line airpressure system. To prove the lightweight frame design, a prototype Twinside trailer has been tested over the pavd and concrete sett tracks at the F.V.R.D.E., Chohham.