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More pictures and information at http://www.jh-create.com/2012/09/komatsu-840-forwarder.html
The entire design except for the joystick controller is mine (some inspiration for the bogies by dhc6twinotter). It took a few months and alot of time and patience, the entire model has been rebuilt from scratch at least 7 times. I am especially happy with:
- How the crane operates and behaves, very similar to a real machine
- The stability of the chassis
- The stability of the bogies (they are subject to very heavy forces when turning). However, they are quite complex, each bogie is built by more than 100 pieces.
- Although alot of functions, the slim body of a forwarder has been kept. The main chassis is just 5 studs wide (since the pendular bogies requires alot of space).
- The ground clearance is almost 5 studs.
Objectives
- Authentic proportions
- Mechanical crane (not pneumatic)
- 100 % remote controlled
- Joystick controlled
- Strong enough to actully load and carry small logs in the forest
Functionality
- Forward / reverse with 8WD
- Articulated steering
- Rotating hitch – Independent tractor and trailer
- Locking mechanism for rotating hitch
- Working bogie axes
- Boom Slew
- Boom up/down
- Jib up/down
- Grapple open/close
- Grapple rotate
- Fake 4 cylinder engine
Datasheet
- Propulsion: 2x PF XL motor connected to a common drive train
- Steering: Frame steering by two small linear actuators powered by a PF M motor
- Hitch lock mechanism: Micro motor
- Boom Slew: Large turntable turned by PF M moto
- Boom Up/down: LA powered by PF M moto
- Jib up/down: LA powered by PF M motor
- Grapple open/close: Wormgear driven by PF M motor
- Grapple rotate: Micro motor
The grapple. Rotated by a micro motor in the back. Open/closed by a PF M-motor in the crane based, connected using 5 U-joints in order to not decrease the operating range of the arm. The grapple can "swing" in two directions.
Authentic control. The joysticks control the arm exactly as in a real forwarder. The remote control turned upside down is used for controlling the grapple open/close with your index finger. By switching channel the joysticks can be used for driving and steering. The joystick design is by jjrailton.
The small black gears can be locked from turning (lock the rotating hitch) by a micro motor underneath the cabin. This is in order to stabilize the crane and the chassis during loading (the crane is subject to quite strong forces during loading). This function is also used in the real machines.
9 wires (!) and the drive train is passing by the rotating hitch / central joint. In totalt there are more than 5 meter of wire hidden in the chassis.
By
JHCreate
Help your fellow builder by leaving your feedback based on these three criteria:
- Originality: How original is this - never seen before?
- Building Techniques: How much skill do you think the creator of this MOC has, in terms of building technique?
- Details: Express how much you like the details of the build.
Your feedback is only shown to the creator as well as yourself. It is not available for other users to see. The creator won't see your user name.