Helical Gear

A few weeks ago, we did something to our Hollow block mould to improve the shape and size of our resulting blocks. This resulted to a heavier mould - my guess would be about 40kgs added from the existing 150 kgs. Unfortunately, the machine's mechanical gear box seemed to experience difficulty in lifting the the entire mould box together with concrete materials (approx 100kgs) inside. It was able to function for about a week, but afterwards, it seemed frequently to stop about half way through lifting. 

Gearbox minus the gears and shafting

We were too lazy to take the machine apart and expose the gearbox. So we first thought about the 3hp induction motor that was driving the gearbox to be the culprit. Hence, we checked its A.C. Contactor and replaced it with a new one. Nope, that didn't work. We finally decided it was the gearbox. 

 

The damaged gear with its shafting (plus someone not wearing safety shoes)

 We took it apart and voila, the 10 inch helical gear was missing a number of its teeth on two different areas of the circumference. We foolishly thought there would be a replacement gear readily available in your leading hardware stores. Surprise surprise, it had to be machined. In the end, we had to have the entire gear fabricated using hardened steel. The old one was made out of casted steel.

Damaged gear with missing teeth. If it doesn't have teeth, then it sure won't bite!

The machine shop told us to always check for the acceptable loads to avoid future problems with the gearbox. Also check alignments, not to over-tighten the belts, ensure proper lubrication of both gears and bearings. Well, we failed miserably on step number one alone. Lesson learned. But that single gear wasn't the only problem. 

To be continued..