Reply To: Collab 2020: Modeling Heavy Equipment (Backhoe)
@theluthier Stop the press! It turns out I am not today’s hero after all – at least, not quite as much as I was given credit for!
In the stream you asked me to double-check whether the schematic I found was really of the 434E, or was actually of some other model. I did manage to verify that it IS from the 434E, there is no doubt.
H O W E V E R…
The discrepancies between the drawing you provided and the schematic I found were too great to ignore, especially since your drawing is from an official source, the brochures that come from CAT itself. Looking at the photos in those brochures for the 434E, I saw a swing frame that is unmistakably the kind that appears in YOUR reference drawings, not mine. I was very confused by this, so I began digging even deeper and I solved the mystery once and for all.
Both styles of swing frame are correct, technically.
Here is a 2008 434E with the style I made:
And here is a 2012 434E that clearly has the style that appears in your brochures:
Sometime between the 2008 and 2012 model years the entire swing frame AND digger arm assemblies were upgraded for the 434E. Notice that the 2012 model’s digger arm matches the one you’ve been modeling, while the 2008’s arm is different. I’m not going to post all the photos and videos I looked through checking up on this; suffice to say that IMO the two digger arms are substantially different, mechanically, not just visibly different.
Since everyone else has been working from the references of the newer model, I’ve decided to change my swing and slide frames; the differences are too big for me to be willing to ignore. But this does mean that I’d like you to take back your modification from the stream, and re-align your digger arm’s hinge and latch pins with the positions on your reference, ignoring mine. Your reference is correct for this part, and I’ll be changing mine to match it. Anything worth doing is worth doing right!
Speaking of videos, I found a couple of videos that might be of interest to you. The first one shows some close-up, good-resolution video of parts of the digger arm and its components that it’s hard to find on image searches:
https://www.youtube.com/watch?v=ajV-phNXUCo
The second one shows both the digger arm and the front-loader in action, mechanically, in a way that really helped me visualize how everything works together. @blanchsb may want a look at this video too, since it shows (if you look closely enough) how the “jaw” function and those two pistons on the outside ends of the front-loader bucket work.
https://www.youtube.com/watch?v=EEDBFiCVeeQ
Hope I’ve helped a bit!