[JMay]

Some more details on the umpteen Tyre Truer.

See below pics taken from CAD showing the exploded parts of the machine and the assembled unit. The colours show the individual parts and are all 3dp except the metalwork. Shafts are 4mm dia stainless steel with ball races either in the supports or the pulleys/cogs. The mauve support holds the freewheel pulley (marked F) which is on a slide to enable the belt to be fitted then tensioned. The 365 motor is mounted centrally under the axle carrier and drives a pinion and two cogs to increase the torque and lower the rpm to the driven pulley (marked D) on the left hand side. I used threaded brass inserts in the driven pulley, final cog and the axle carrier so that the grubscrews and fixing screws can apply sufficient force repeatedly without chewing up a 3dp thread over time. The axle carrier is on a 6mm stainless steel shaft at the rear acting as a pivot to enable the carrier to swing down onto the belt, controlled by the hex bolt (silver) which has a spring to control the vertical carrier movement. 

   

   


To answer DPJ's question, like a belt sander there is a plate to support the sanding belt at the point of sanding in this case the tyres. The plate rises up from the bed centrally between the two pulley wheels and is @70mm long to cater for various axle/wheel tracks. I added some TPU feet to the unit to reduce the vibration and hence noise when running shown in black.

   

Kevan suggested turning the axis by 15 degrees, this is set at 90 degrees as any deviation from this is limited by the belt width used (10mm wide). Will look into a video as not on YouTube and not sure if I can post direct or have to link to one. 


Cheers
          John