I have a base with 4 wheels, the rear axle is a motor which drives the base forward or backwards, this contains a diff, so there's no problem there.

The front axle is a steering axle like that in a car, except where the steering column would be extends vertically, and not at a diagonal in a car.

In spare parts, I have an arm which is capable of pushing and pulling (depending on which way the DC current goes), and this is affixed to a plate at the rear of the wheel base, and points at 90 degree angle from the plate, towards the steering column. The arm is affixed 20cm to the left of the steering column. I want to use this arm to turn the steering axle.

If I fit another (fixed, non extending) arm onto the steering axle so it can be pushed and pulled, what could I do to connect the two arms so that the extending arm can turn the steering axle? Would the non extending arm also need to be extendable (like a piston)?

Below is a very poorly drawn diagram that I've rushed a bit. The yellow section is the extending arm, the blue bar is the bit for steering. The black bar that extends from the blue bar is the steering column (with the proposed fixed arm pointing left)

Supporting Image



1 Answer 1


enter image description hereA 90 degree crank would do it : like an L : the yellow bar pushes or pulls the horizontal prt of the L and the other end of the L moves the black bar left or right.

Edit added pic, something like :

  • $\begingroup$ Thanks. I think I understand, I will give it a try in a while and get back to you with the response. $\endgroup$ Dec 12, 2017 at 17:15
  • 2
    $\begingroup$ It would be clearer if you (and the OP) marked hinge points, and whether each hinge is free-floating or the hinge pin is locked to a reference frame such as the car body. $\endgroup$ Dec 12, 2017 at 19:32
  • $\begingroup$ Thanks. The edited version of my poorly drawn diagram that totally wasn't done in MS paint really helped to understand what you meant, I did understand what you were saying before, but the diagram has helped. $\endgroup$ Dec 12, 2017 at 20:57
  • $\begingroup$ AKA a bellcrank. $\endgroup$
    – Phil Sweet
    Jan 11, 2018 at 19:12

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