Arocs Tipper Project

Page 2: Upgrades!

When this model was announced, I was surprised to hear that the tipping actuator was not standard. It is quite a shock to learn how much extra you have to spend to get this option, and you may not understand why it costs so much since it is "just a screw". As you'll see below though, there is a lot involved in this optional actuator set, and many of the parts are steel or aluminum. I highly recommend adding it if you own this truck since tipping the bed is the point of a tipper truck.

Here's a good look at the contents of the box. There is a more here than you might expect. The actuator must be able to lie horizontally when retracted, but then pivot to vertical when extended. This is the only way it will fit between the chassis rails and also extend far enough to lift the bed. This requires a mechanism. The electric motor must also be geared down heavily to lift the potentially heavy load in the bed. There is a control unit which takes the signal from either the radio or the manual switch and translates it to a command. Use of the manual switch will always move at full speed, while using the radio allows 3 speed options in each direction. There are also limit switches to stop the actuator when the bed reaches its end of travel. Without these, the huge mechanical advantage of the motor could damage the bed or the chassis running into the stops.

The part you see on the left is the main drive screw and bull gear. If you look closely you'll see a ratcheting clutch built into the gear to protect the system from overload. The right hand image shows the main gearbox. The small motor is at top left and is already connected to an inline gear reduction unit which results in a very slow output. This thin directly drives a pinion which mates with the bull gear. The gearbox housing is aluminum but the screw appears to be steel (which makes it heavy). A thrust bearing sits at the end of the screw to support the axial loads of the actuator.

The traveling nut at the end of the rod is what extends the actuator. The screws fits inside when the rod when the actuator is retracted. The right hand image shows the cylinder (or barrel). This would be a pressure vessel on a hydraulic actuator, but here it really doesn't have any structural function. It makes the whole thing look like a hydraulic actuator and it protects the screw from dirt and debris.

Here is the completed actuator with motor, gear reduction unit, gearbox, cylinder, screw, and piston. On the right you can see the steel plates which serve as links to control the kinematics of the system. The upper end of the actuator connects to the links, and the lower end will pin to the chassis.

The control unit must be sandwiched into the plastic box between the frame rails of the chassis. Into this you must plug the motor, two limit switches, the radio connection, the manual switch, and power. If that sounds like a lot of connections, it is. It is tricky to get everything to fit in the box, especially if you'd like to coil up any extra wire length in there and not have to secure it elsewhere. In fact, routing the wiring is probably the most complex part of the whole installation process. The actuator fills all the space between the rails and it is very important that the space be kept clear for movement. Any wires in the way will get smashed. Yet, power and signal clearly need to run forward, and so do any LED wires that might be going to the tail lights. The wire going to motor must also be able to move through a large arc as the actuator extends.

Here the actuator and the control box and installed to the bottom side of the bed. Everything is unsecured at this point and quite heavy, so the risk of pinching a finger is high.

Here's the installed actuator in the raised position. Just behind the oil tanks on the frame rail you can see the switch for manually raising or lowering the bed. This will work whenever the battery is plugged in regardless of whether or not the ESC is turned on. This means you need to unplug the battery when not in use to avoid total discharge.

From the beginning it was a given that I would be installing the Multi-Function Control unit MFC-03 in this model. Since I've documented such an installation before, I won't repeat it all here. The control of the lifting actuator takes the place of the 4th channel previously used to detach trailers and control motorized legs. The little amber light ahead of the front wheel is not used per the instructions. The lens does have a light bucket, but I assume it is not used because it is too hard to get wires to this location with all the potential interferences in the lifting cab. I was able to solder up my own wiring to make it work.

CChand makes some nice photo etched options for this truck. I didn't really like the stickers that came with the kit to install a diamond plate pattern on the rear fenders. I thought they looked much too fake. These metal parts, on the other hand, actually have a real textured diamond plate pattern and look awesome. 100x better.

This compares the original grille center logo with the lighted version I got. You use the same chrome emblem in either case. There happened to be an open slot on the MFC which allowed for easy attachment of the lit logo which comes on with the fog lights.

Here is the installed illuminated logo. I'm pretty sure the maker starts with an actual Tamiya part and modifies it with the light unit rather than making a new part from scratch. It fits perfectly, therefore.

I vacillated on whether or not to buy this bed liner for a while because it is rather expensive, but it just looks so fantastic that I couldn't resist. It contains sheets for the bottom of the bed and all four sides including the rear gate.

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