[SEL] OT: Splitter Boxes and Range-Changes

[Listerdiesel]

For those non-truck guys who might be interested, the term splitter
box refers to a 5 or 6-speed gearbox with another (epicyclic) gearbox
on the back, giving a multiplication up or down of the difference
between two consecutive gears in the main gearbox, thus you would
start in 1st Low, then split up to 1st high, then 2nd low, 2nd high
and so forth.

Range-change boxes were a development of the splitter boxes, except
that the ratio of the epicyclic unit took the gearing up a whole range
of gears higher, and once in the high range you rarely needed to come
down again on the move, so the sequence went 1st, 2nd, 3rd, 4th, 5th
then back to 1st but you changed the range up so that 1st was now 6th
gear and so on.

There were all sorts of devices to stop folks dropping back down the
range at the wrong time, and when they failed it was a case of a box
of cogs all over the road! The Scania box in particular was prone to
all sorts of problems with the pneumatics and synchro cones.

Fuller made a Range-Change box which also sold well in the UK, but
Volvo and Scania made their own units.

Having driven both (I hold a full truck licence) I found the splitter
box better, but the constant thumbing of the control button on the
gear lever didn't suit some guys, and the range-change boxes
eventually replaced the splitters completely.

Peter
-- 
Peter A Forbes
Email: listerdiesel at gmail.com
Web: www.oldengine.org/members/diesel