Method for opening a combination padlock

A method of determining the three number combination of a locked padlock of the type having a casing, a shackle, a rotatable dial having position indicating marking thereon on the outside of the casing for rotating first, second and third wheels about a common axis with each wheel having a gate slot in its edge for receiving a fence which is movable toward the three wheels upon force being applied to the shackle in a direction to urge the shackle to an open position, wherein rotation of the dial rotates the third wheel which in turn can rotate the second wheel which in turn can rotate the third wheel to align all of the gate slots to allow the fence to fit fully into all of the gate slots to allow the shackle to be moved to an open position, said method comprising the steps of:

• rotating the dial to incrementally move the gate slot of the third wheel in alignment with the fence,
• applying a force to the shackle in a direction to urge it to its open position and, with a movement sensing means, visually obtaining a measurement representative of movement between the shackle and the casing to find the third number of the combination reflected by movement of the shackle when the gate slot of the third wheel is aligned with the fence,
• rotating the dial to incrementally move the gate slot of the second wheel in alignment with the fence and to move the gate slot of the third wheel in alignment with the fence and applying a force to the shackle in a direction to urge it to its open position and with said movement sensing means, visually obtaining a measurement representative of movement between the shackle and the casing to find the second number of the combination reflected by movement of the shackle when the gate slots of the third and second wheels are aligned with the fence,
• rotating the dial to incrementally move the gate slot of the first wheel in alignment with the fence and the gate slots of the second and third wheel in alignment with the fence to obtain the first number of the combination and/or to open the shackle of the padlock.

For determining one or more numbers of the combination for opening of a locked combination type padlock having a casing or body, a locking shackle and a series of wheel-like, notched tumblers which can be turned in a known manner by a rotatable dial to successively position the tumbler notches into alignment with a fence whereupon an opening force on the lock shackle will effect opening of the lock, the dial having incremental markings for indicating its rotational angular movement from a zero position, the method comprising:

• a. utilizing a sensing device to indicate a value of relative movement occurring between the shackle and the body of the lock when a lock-opening force is applied therebetween;
• b. rotating the dial to successive dial increments;
• c. applying a lock opening force between the lock body and shackle at each of said successive increments;
• d. determining from the value provided by the sensing device when relative movement occurs between the lock body and shackle at each said successive increments;
• and
• e. noting as one number of the combination the dial position when the value indicated for the relative movement due to one of said successive dial increments returns to the value of the dial increment immediately prior thereto.