Rigged and textured model of manual pallet jack (pallet truck)

Model is created and rigged entirely in Blender and partially textured in Substance Painter.

I've tried to create mechanically accurate model and rig it by following laws in mechanics. Speaking of mechanics, rigging is mostly done with drivers containing various formulas (axial rotation, trigonometry and such a things). Also, few armatures and some constraints are used in that process. I've never done any rigging beforeso my way of doing it is mostly done with help of knowledge of math and mechanics, instead of conventional rigging mechanics. And it finally works in a way it should work after many failed attempts.

Rigging is done with five controllers (I've used arrows created as mesh instead of empties for better visibility only. Those controllers are disabled while rendering ( listed and explained below):

• Main controller - allows you to move (translate), rotate and scale entire model (all 60 objects it contains). Translating controller along local X axis affects rotation (accurate) of steering and load wheels.
• Lift controller - allows you to move forks up and down. Forks lifting is mechanically accurate and is based on axial rotation of main lifting arms (back arms attached to steering axle). That means forks are also moving slightly front and back (local X axis) wich affects rotation of load wheels. Back arms are connected to pushing rod (under the forks) that controls rotation of front arms, used to push down tandem with load wheels and lift up front side of forks (and vice versa).Lift controller is used by moving it along local Z axis.
• Steering controller - is used to steer pair of wheels the closest to the driver (steeding wheels, the biggest ones) This controller controlls rotation of entire steering group that contains objects like handle, hydraulic pump, steering wheels, etc. Steering is done by rotating controller around local Z axis (limited to angle of -55 to 55 degrees CCW). This also affects rotation of both steering wheels (they rotate in opposite directions).
• Handle controller - is used while driving or raising pressure of hydraulic pump that lifts forks. This controller can be rotated from 0 to -74 degrees and affects pump's spring compression.
• Handle lever controller - is used to open/close pressure valve on hydraulic pump. Here has demonstrational purpose only. Move controller along local Z to simulate positioning of handle lever (its rotation).

I've checked all parts of model to be sure they contain quads only and really hope I haven't missed any non-quad to fix.Almost all parts have added subdivision modifier(not applied) that make total number of polys pretty high (with subd level 2 or 3 over million) but parts before modifier are mostly very low on polygons.

I've created this model for illustrations in mechanics where textures are not much important but here I've done some on big parts using Substance Painter (basically materials with some dirt and edge wears). Textures are both, packed inside blend file and provided in separate archive. Parts of the model are all seamed and unwrapped but some of those unwraps are not used here. Anyway, now you can easily group objects you want to texture and unwrap them in order to make own custom textures to (replace mine). All previews here are rendered with Cycles.

Note: I haven't exported model into FBX and OBJ/MTL because I don't use 3D software other than Blender and can't check and guarantee for those exports. Anyway, Blender is free and everyone can do export settings to fit their needs. I'm mostly concerned about how other software handle rigs from Blender so it's safe for me to provide Blender version only.

Any feedback is more than welcome.