Okay, catching up on this side project build - been busy setting up a new computer, and all the time that always takes! Will be better suited for all the CAD work I am doing these days, so well worth the time. Anyway, I got the part in to switch the cylinder pair that holds up the entire boom assembly over to single-start Acme threads vs the original 4-start threads, which were just too aggressive on the movements. Here is the base assembly:
Each cylinder has its own drive shaft - in the picture the one on the right has a small drill chuck on it to make it easier to turn by hand. With the new leadscrews I can turn the shaft and lift/lower the booms with just one cylinder and a reasonable amount of force. Before, that was very difficult. The two shaftws will come back to a common drive gearmotor, have not decided if I'll do a gearbox to link them or use a small chain drive (leaning that way at the moment).
Here is a picture showing the entire assembly, bucket lifted off the table - stays there now, before it could spin the leadscrews and lower itself back, which meant that it would have been putting constant strain on the motors.
Lots of spare shafts and couplers in the foreground from figuring out the whole thing.
Here is a shot showing the part for holding and spinning the cab - there will be a lot of side force at times, so I wanted a strong way to connect things. Wound up with a spare set of tapered roller bearings from a trailer - figure it will be more than strong enough! The gear will be mounted to the track unit underneath, and a motor drive gear in the cab will engage it and turn the cab. There is a slip ring unit there to take the motor leads for the track drive motors down from the cab to the lower unit, but still allow the cab to turn as many full circles as it wants. The spindle will be home made, hollow unlike a normal car axle end to allow the wires through.
04-02-2020, 12:54 PM
Re: Cat 340D Excavator build
Hybrid Mode
