Slope Lock in Automobile Gearbox


Prevents backward trailing of vehicle by allowing shaft motion in only one direction


Patent application no. - 396/BOM/96


The lock is a Ratchet-Paul mechanism that stops the main shaft of transmission from revolving in reverse direction. This prevents the vehicle from moving backward (it prevents forward motion if vehicle is in reverse mode).The mechanism works such that two plate are engaged to each other when the vehicle (shaft) is not in motion.

The plate has Ratchet Paul Mechanism which allows rotation of the shaft in only one direction. The mechanism locks if shaft is rotated in another direction due to locking of two plates forming mechanism

When the shaft is set in motion, the two plates are pulled apart from each other due to centrifugal governors.

  Invention (What is New)  

Slope lock in gear box Prevents backward trailing on slopes. The lock stops working after vehicle is set in motion in desired direction.

  Diagram & Description  
Shaft 8 locked due to Plate 2 and 3 locked with each other and cannot move in direction shown as A 
SlopeLock Raw Image
Original Pencil Drawn Images.

Direction A, Plates locked due to 4 locking with each other.
Direction B, Plates move as to 4 slide over each other.
Shaft 8 rotating in direction shown as B while plate 2 is pulled apart from plate 3 due to centrifugal governors shown as  1 and 6
Another Version
  Slopelock  Another version of slope lock that is unlocked when wheel is turning in clockwise direction. and the lock is held by an electromagnet. As the wheel stops, the lock is released by electromagnet and it falls down locking its teeth with wheel gear. In this position the wheel cannot move in anti clockwise wise direction thus allowing motion only in one direction.
Fitting this lock in gearbox prevents backward trailing of vehicle. (This eases driving while climbing slopes and also avoid accident prone situations)