The mechanism of the Add-em toy adding machine

In this video I want to show you I have already removed the three buttons I have already removed the three buttons by pulling them off the stems and separated this top case from its base. but the carry mechanism. This one is three parts welded together. And it’s attached to the base with these tab and slot fasteners. Each button, it moves a wheel The three digits are each powered by these buttons, but the carry mechanism. well, it’s not really a proper carry mechanism. It doesn’t cause one wheel to move But notice that if I turn this wheel Instead when a carry needs to be performed, the buttons directly drive the wheels that need to turn. But first things first.

01:20 - Each button, it moves a wheel through this straightforward latch mechanism. Lets have a look at the carry from the 10s to the 100s. that ensures that the wheel cannot move backwards but only can move forwards. It uses this saw-toothed gear on the side, and on this end is a pawl that pulls on a tooth when you push down the button. So in that way the wheel can just move around.

02:00 - But notice that if I turn this wheel all the way around by hand, A similar thing is going on from the 1 to the 10. and yet when I push this button… … the carry is performed. The other buttons also drive their respective wheels in the same way. this gear on the tens wheel also has a deeper notch when it reaches 9 and uses the left side of this hundreds wheel and similarly the tens button uses That gear is attached to the axle onto it so that it can’t rotate separately from The pawl uses this gear on the left side of the 10s wheel but the notch between the… the notch next to the nine is slightly deeper When you reach this gap, and it starts to engage the gear on this number wheel. That’s the mechanism of the Add-em toy calculator.

Thank you for watching! 03:27 - so now that same pawl pulls both wheels at the same time. And now it only pulls on the tooth of that 10s wheel because it now no longer reaches down to the 100s wheel, until it gets to this deeper notch and it pulls both. A similar thing is going on from the 1 to the 10. The units button, it has one pawl that moves the units wheel itself and another pawl here to handle the carries. On the left of the unit’s wheel is a smooth ring but it has a gap when it reaches the 9 and that allows that pawl to move a bit deeper and engage with the 10s wheel.

04:37 - So that’s very similar to what we saw here, but this gear on the 10s wheel also has a deeper notch when it reaches 9 and when that happens the pawl can reach deeper into that gap in the smooth ring on the units wheel and engage with a metal gear underneath. That gear is attached to the axle and the axle has this hundreds wheel fixed onto it so that it can’t rotate separately from the axle, So when this pawl pulls both the parts here, both the gear on the 10s wheel and the metal gear that connects to the hundreds wheel, that’s when both carries happen automatically. So let me show that again. When you reach this gap, the pawl can reach down and move the metal wheel underneath. That’s the mechanism of the Add-em toy calculator. Thank you for watching! .