Answers.Body: <p>After some searching I've found <a href="https://board.ttvchannel.com/t/motorized-bump-n-go-mechanism/71295" rel="nofollow noreferrer">a thread on the TTVChannel</a>, where user <a href="https://board.ttvchannel.com/u/Bioman" rel="nofollow noreferrer">Bioman</a> posted some photos and a <a href="https://www.youtube.com/watch?v=ar2eJ6fuWTg" rel="nofollow noreferrer">video</a> of his build of a bump and go car:</p>
  <p><a href="https://i.sstatic.net/rTzGAqkZ.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/rTzGAqkZ.jpg" alt="View of the vehicle from above, showing a reduction gearset powering a vertical axle across the vehicle frame" /></a></p>
  <p><a href="https://i.sstatic.net/26jUZ64M.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/26jUZ64M.jpg" alt="View of the same vehicle from below, showing the veritcal axle to terminate in a bevel gear that meshes with another bevel gear on a horizontal axle mounted on a frame that can freely rotate around the first axle" /></a></p>
  <p>The mechanism is fairly simple: when the vehicle is running unobstructed, the rotation of the axle across the frame is transmitted to the wheels via the pair of bevel gears. But when the car hits a wall, the wheels can't turn anymore, rendering the horizontal axle temporarily fixed - but since the motor is still running, the rotation causes the entire lower wheel mount to turn instead, until the wheels are free to roll again.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2024-12-21T13:40:14.897Z
Answers.Text: Thanks for the clear photos. I managed to build it and it works!
Answers.UserDisplayName: user2337857
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2024-12-21T13:41:31.477Z
Answers.Text: thanks for the clear photos. I managed to build something similar and it works as intended.
Answers.UserDisplayName: user2337857
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2024-12-20T09:33:04.137Z
Answers.LastActivityDate: 2024-12-20T09:33:04.137Z
Answers.UserDisplayName: zovits
Body: <p>I am trying to build a bump and go motorized toy with bricks.
  This type of mechanism is found in children toys and below is a description of the behaviour.</p>
  <ul>
  <li>the car has a small set of wheels that sit on a circular plate.</li>
  <li>if you lift the car in the air, the wheels have no friction at all. And the wheels will stop spinning, but the plate will rotate.</li>
  <li>When the car is put on the floor, there is too much friction for the plate to spin. So the wheels receive the power and the car will move forward (or backwards, depending on the direction of the plate)</li>
  <li>when the car bumps into something the wheels will have more friction, and the plate will spin and the car will turn.</li>
  <li>note that the plate can spin 360 degrees.</li>
  </ul>
  <p>Does anybody have an idea of how to build this mechanism?
  attached is a picture of such a car</p>
  <p><a href="https://i.sstatic.net/YFM7dhSx.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/YFM7dhSx.png" alt="enter image description here" /></a></p>
  
Tags: <gears><mechanical>
Title: differential mechanism for a 'bump and go' car
UserDisplayName: user2337857
ThreadText: # differential mechanism for a 'bump and go' car
  
  (Asked by: username_0 on 2024-12-20)
  
  I am trying to build a bump and go motorized toy with bricks.
  This type of mechanism is found in children toys and below is a description of the behaviour.
  
  * the car has a small set of wheels that sit on a circular plate.
  * if you lift the car in the air, the wheels have no friction at all. And the wheels will stop spinning, but the plate will rotate.
  * When the car is put on the floor, there is too much friction for the plate to spin. So the wheels receive the power and the car will move forward (or backwards, depending on the direction of the plate)
  * when the car bumps into something the wheels will have more friction, and the plate will spin and the car will turn.
  * note that the plate can spin 360 degrees.
  
  Does anybody have an idea of how to build this mechanism?
  attached is a picture of such a car
  
  [![enter image description here](https://i.sstatic.net/YFM7dhSx.png)](https://i.sstatic.net/YFM7dhSx.png)
  
  **Tags:** gears, mechanical
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2024-12-20. Score: 3 | Accepted answer
  
  After some searching I've found [a thread on the TTVChannel](https://board.ttvchannel.com/t/motorized-bump-n-go-mechanism/71295), where user [Bioman](https://board.ttvchannel.com/u/Bioman) posted some photos and a [video](https://www.youtube.com/watch?v=ar2eJ6fuWTg) of his build of a bump and go car:
  
  [![View of the vehicle from above, showing a reduction gearset powering a vertical axle across the vehicle frame](https://i.sstatic.net/rTzGAqkZ.jpg)](https://i.sstatic.net/rTzGAqkZ.jpg)
  
  [![View of the same vehicle from below, showing the veritcal axle to terminate in a bevel gear that meshes with another bevel gear on a horizontal axle mounted on a frame that can freely rotate around the first axle](https://i.sstatic.net/26jUZ64M.jpg)](https://i.sstatic.net/26jUZ64M.jpg)
  
  The mechanism is fairly simple: when the vehicle is running unobstructed, the rotation of the axle across the frame is transmitted to the wheels via the pair of bevel gears. But when the car hits a wall, the wheels can't turn anymore, rendering the horizontal axle temporarily fixed - but since the motor is still running, the rotation causes the entire lower wheel mount to turn instead, until the wheels are free to roll again.
  
  > **Comments:**
  > **username_0**: Thanks for the clear photos. I managed to build it and it works!  
  > **username_0**: thanks for the clear photos. I managed to build something similar and it works as intended.  
  
  ---
  
  