I have no idea.
CMC fatality
- Thread starter deevo
- Start date
Reach
Been here much more than a while
- Location
- Atglen, PA
I would think it should, as it does reinforce the boom on the place where it’s been breaking. We have one with the upgrade plates installed, and they definitely appear to reinforce the right area.
Thank you
Quick update: I’ve definitely progressed every week since the fall. Still have lingering pain in certain areas but nothing abnormal due to my injuries. I’m in the work hardening program attempting to get myself close to my capabilities before the incident. I got cleared back to work on the 4th of this month, only sedentary with a lot of restrictions. Just got cleared to work 1 day in the field per week on Tuesday. In general I’m forever grateful. Also I still have much work to do for maximum recovery.
I hope & pray it’s bombproof
Reach
Been here much more than a while
- Location
- Atglen, PA
Very glad to hear your recovery is progressing well, I hope and will be sure to pray too that you are soon back to normal completely!
I hope ours is bombproof too. I do inspect it carefully, and we run it gently.
Cut and chuck with the boom near full reach horizontal could be hard on the boom. I’ve also found that transitioning between functions can bounce that boom pretty hard if the second function is raising the upper boom, and that always worries me because I know how much force that can add.
Chris Schultz
Carpal tunnel level member
- Location
- Minturn
Kind of ironic often there is a CMC add banner at the bottom of this page…
Chaplain242
Branched out member
a
Nope the reinforcement didn’t push the weak spot to another part of the boom. Time will tell…
VenasNursery
Been here much more than a while
- Location
- Michigan
I’m glad to hear been thinking about you
I hope you have a full recovery
Gorman
Branched out member
- Location
- Rhode Island
True
Thank you
I commend your due diligence inspecting and making wise decisions to reduce forces on the machine itself. I pray and hope that keeps your machine from failing. Stay safe
Thank you
Stay safe and Blessings
ghostice
Been here a while
If a machine is advertised for arborist use, I would think that “cut and chuck (within reason), would be part of “typical reasonably forseeable use” by an arborist. However if it was originally designed for only the weight of an operator and paintbrushes and a gallon of paint, then that’s another thing. A lawyer if they know anything about engineering would ask about the equipment’s original design basis. The design rating would also have to cope with movement or momentary loads much like a crane pick that’s not “quiet” (e.g. breaking a bypass cut) - these loads can be momentarily higher and should probably reasonably be expected to be part of the design basis as well (big big safety factor?). My 2 centz this morning.
southsoundtree
Been here much more than a while
- Location
- Olympia, WA
I wholly disagree.
What is a load rating worth if it changes for second to second... i only overloaded my spine/ carabiner/ rope/ etc for 1 second, maybe 3.
Isn't 500 pounds (a vector force, weight, nothing to do with mass---works on the moon, and earth) specific enough?
Shouldn't there be force-meters on this equipment, like required on a crane?
What is a load rating worth if it changes for second to second... i only overloaded my spine/ carabiner/ rope/ etc for 1 second, maybe 3.
Isn't 500 pounds (a vector force, weight, nothing to do with mass---works on the moon, and earth) specific enough?
Shouldn't there be force-meters on this equipment, like required on a crane?
Last edited:
Reach
Been here much more than a while
- Location
- Atglen, PA
There is a force meter (actually several) on the 83HD we have, visible on the screen on the side of the machine. It shows both the weight-in-basket in pounds and the percentage of capacity at that radius.
I’ve used it to confirm that we are not exceeding capacity when doing cut and chuck at far horizontal reaches.
ATH
Been here much more than a while
- Location
- Findlay, Ohio
Isn't that why kN come into play instead of pounds?
ATH
Been here much more than a while
- Location
- Findlay, Ohio
That doesn't keep a record of those forces, does it? THAT would be great information to see.
Reach
Been here much more than a while
- Location
- Atglen, PA
I don’t know, but it would be very interesting to see if it does. It’s amazing how much data that little screen shows actually, position of both booms and basket in real time, pressure on each outrigger, it’s all something. Makes me wonder if there is a little black box on there somewhere, but probably only CMC knows that. If there is, it sure would take some of the mystery out of these failures.
southsoundtree
Been here much more than a while
- Location
- Olympia, WA
Can you give any examples of the increase in force with cut-and- chuck, @Reach ?
Reach
Been here much more than a while
- Location
- Atglen, PA
I’m not sure what you’re asking exactly? I’ll take a guess, but if you can clarify I’ll try to better answer your question.
When you’re doing cut-and-chuck, you’re cutting a piece and holding the weight of the piece yourself, which adds weight to the lift. If you’re taking larger pieces, you’re catching the weight as it drops, which adds a dynamic load to your body and by extension, to the lift basket.
When you’re handling logs that way, a 50+ pound log being cut and thrown off the top of a spar can easily add 80-100 pounds of force to the basket. If you are at full extension, where the LMI on the basket stops you from extending further with a 250 lb load in the basket, that extra 80-100 pounds of force while you’re throwing logs is considerable, especially if you multiply that by the 35’ of boom extended out the side.
Your capacity will increase with a higher boom angle, like in a crane, hence my hesitation to add any dynamic loading at full horizontal extension - it’s the point where the boom is most heavily loaded and therefore weakest.
Chris Schultz
Carpal tunnel level member
- Location
- Minturn
Well said @Reach
