Released in , set has the first and only motorized pneumatic find on any LEGO® model, and in fact this is the only set with a motorized compressor. Find great deals for LEGO Technic Air Tech Claw Rig (). Shop with confidence on eBay!. Shop LEGO Technic Air Tech Claw Rig. Free delivery and returns on eligible orders of £20 or more.
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LEGO Technic Air Tech Claw Rig (8868)
To solve this, the ring gear of the second differential is located on the opposite side. This can be seen clearly in the animation. One is on each axle, and one planet gear in the middle allows the axles to turn at different rates. Flex system rigid sleeves are used as pneumatic tubes to span the sections between the pneumatic hoses.
The second axle drives a pair of 16 tooth spur gears and then the steering rack via an 8 tooth pinion gear. Model by Eric Albrecht. The second section is movable and is lifted by a single pneumatic actuator driving another pair of triangles.
A combination of an 8, 24, and another 8 tooth gear pass the torque up without changing the gear ratio or direction. Click for an animation of the differentials in motion. The steering mechanism itself uses steering arms and toothed links as shown in the computer image. With a compressor, 4 switch valves, 4 large actuators, one small actuator, and four rigid tubes, there are a total of 23 flexible pneumatic hoses to route through this behemoth.
This makes the engine turn fast.
Engine The rear wheels are used to drive a V-6 engine. Click for an animation of the claw in motion.
While this allows them to rotate at the same rate, it could make one differential rotate backwards. A vertical axle which connects to the 16 tooth gear drives a horizontal axle which passes through the holes in the upper turntable. Click for an animation of the 886 slewing. The overhead control drives an axle connected to a pair of 14 tooth bevel gears.
Because of the very small area, this actuator has a small output force and the grip of the claw is not very strong, but it does the job. A real hydraulic actuator has significantly less output force in tension than in compression due to the fact that the annular area of the rod end of the cylinder is less than the full bore area of the head end.
The color coded computer image shows the way the dual pneumatic cylinders are cross connected. Because the crank pins are each offset degrees, the forward and back cylinders are synchronized. The steering arms may seem small for a model of this size, especially since the weight of the model is cantilevered out the wheels via only a single hole as a support couple.
The front of the crankshaft uses a 3 blade rotor as a fan. Unlike the other actuators, this one has to work in both tension and compression, and in fact the lower tension force is what is used to close the claw.
The actuator attaches almost half way along the length of the boom.
Instructions For LEGO 8868 Air Tech Claw Rig
The compressor has plenty of pneumatic pressure to lift the boom, even at full extend. The color coded computer images can be used to decipher the routing of the hoses in this system, which can legoo be used to derive the logic of this mechanical computer. Due to the small gear ratio, it operates very fast.
Click for an animation of the boom in motion.
The claws are supported by 3 arms which are free to pivot at the ends. This allows the claw to remain perpendicular to the ground no matter what the jib angle is.
Reciprocation on this crank gives the compressor cylinder a stroke of 1 stud. Because there is continuous supply of pressure, this model operates very smoothly and multiple functions can even be run concurrently. This allows them to be clipped to hooks which makes certain that the hoses move with the boom and jib and do not become tangled. While tandem rear wheels would have been nice, there is no way they would have fit into the width of this model. Many of these hoses then pass aft through another beam and up through the center of the turntable for the loader.
One or two of the pneumatic air tanks which came out years later make great replacements for the fuel tanks and really bump the functionality up to the next level with a virtually limitless source of pneumatic power. I’m sure no one will have any trouble finding a place to route even more pneumatic hoses!
Air Tech Claw Rig | Brickset: LEGO set guide and database
A look at this computer image and those in the above sections will demonstrate that the hose’s path to this actuator is pretty circuitous. It is important to get the two actuators even and centered when rigging the system to make sure that it can rotate 90 degrees in either direction.
Compared with the boom actuator, this one has fairly poor mechanical advantage, but less is required due to the decreased moment arm of the lifted load.