Steering mechanism of quad bikes, cars, military vehicles etc are based on rack-pinion gear mechanism whose moving parts often get exposed to terrain conditions like boulders and ice slabs in cold countries. These land features may hit the rack gear. Steering mechanism of reverse trikes is based on kingpin assembly which is not responsive enough to handle complicated traffic situation or terrain conditions. Rack pinion mechanism may be too bulky and complicated for reverse trikes.
Basic idea: Steering action at the center is transmitted to steering system on left and right wheels via Bevel-Pinion gear set mechanism. This steering mechanism consists of Central steering system (CSS), left steering system (LSS) right steering system (RSS) steering transmission mechanism (STM).
(CSS) consists of central head tube (CHT), central steerer rod (CSR), central bevel-pinion gear set (CGS).
(CHT) is two vertically oriented coaxial tubes, upper tube (CUHT) and lower tube (CLHT) separated by a distance and connected to top tube and down tube respectively of reverse trike. (CUHT) and (CLHT) are connected by U-shaped rods (CUR1) and (CUR2) on the front and rear side. (CSR) is a rod connected to handle at upper end and coaxially mounted on (CHT) via ball bearings. (CGS) consists of bevel gears (CB1), (CB2), (CB3), (CB4), (CB5) and (CB6). (CB1) and (CB2) are vertically oriented oppositely facing bevel gears coaxially mounted on (CSR). (CB1) is fixedly connected and (CB2) is journalled via coaxial ball bearing to (CSR). (CB3) and (CB4) are oppositely faced gears journalled via ball bearings on (CUR1) and (CUR2) respectively and meshingly engaged with (CB1) and (CB2). (CB5) and (CB6) are bevel gears fixedly connected to (STM) and meshingly engaged to (CB1) and (CB2) on transversely left and right side respectively. (LSS) and (RSS) have similar arrangement with steerer rod connected to crown of fork of corresponding side wheel.
(STM) consists of transversely oriented left transmission rod (LTR), right transmission rod (RTR) left steer transmission tube (LTT) and right steer transmission tube (RTT). (LTR) coaxially connects (CB5) to right side bevel gear of (LSS) and (RTR) connects (CB6) to left side bevel gear of (RSS). (LTT) and (RTT) are tubes coaxially rotatably housing (LTR) and (RTR) respectively via ball bearings. (LTT) and (RTT) are appropriately connected to reverse trike frame. Forks on the two wheels may have suspension rods. In reverse trikes one can have smaller front wheels without loss of steerability.
When rider rotates (CSR) clockwise (LTR) and (RTR) rotates in opposite direction which turn rotate upper bevel gear of left and right steering system respectively in clockwise direction and vice-versa.