Some robotics games have an element of play where there is a competitive advantage to throw game objects. These assemblies are typically attached directly to the robot chassis.
They are usually activated using a motor, a motor with a gear/sprocket system, or a pneumatic cylinder system. Active throwing manipulators are often paired with sensors to help control the throw. They also require a great deal of planning and time to assemble.
These manipulators usually consist of a pickup and transfer system and a throwing system such as:
Roller Intakes and Conveyor Belts
Roller intakes and conveyor belts move game pieces from the game field into the robot and usually into another manipulator.
These manipulators are activated using a motor or a motor with a gear/sprocket system.
Roller intakes can be assembled using the Intake Rollers or wheels.
A custom assembly for roller intakes can be made using High Strength Sprockets fixed to a shaft with a span between the sprockets and rubber bands, latex tubing, and/or Anti-Slip Matting run between the sprocket sets to create a roller. A series of zip ties tighten to a shaft side by side can also make an effective intake roller by brushing the game pieces into the robot.
Roller intakes typically spin faster than the robot can move forward.
Conveyor belts are typically assembled using the Tank Tread Kit, the Tank Tread Upgrade Kit and/or the Highest Strength sprockets and chains. They are used to move game pieces within the robot.
|Intake Roller||Conveyer Belt|
Flywheels, Slingshots, and Catapults
Flywheels, slingshots, and catapults are specialized manipulators which are designed to fling or throw game pieces.
They are assembled using Structural, Motion, and other VEX products. They are often paired with sensors to help control the throw.
These manipulators take a considerable amount of time and planning to assemble.
Flywheels throw game pieces by having the game piece come in contact with a spinning wheel. These wheels can be aligned in pairs in which a game piece is spun out from between the two wheels or a flywheel can also be assembled with a single wheel combined with a friction plate which the game piece rolls along.
Flywheels spin at a very high speed in order to throw game pieces.
Slingshots can be assembled using a Linear Motion Kit. The game piece is placed on a game piece holder and is mounted to a Linear Slide Track which has a series of Rack Gears mounted to the slide.
Rubber bands or latex tubing are attached to the game piece holder and fixed on the other end to the chassis. A motor and spur gear are assembled in the Rack Gearbox Bracket and attached to the chassis. The Game piece holder/linear track assembly is inserted into the Rack Gearbox Bracket with the rack gears intermeshing with spur gear.
The motor rotates the spur gear and it moves the Linear Track assembly back stretching the rubber bands/latex tubing of the slingshot.
The key to this assembly is a small number of teeth are removed from the spur gear. When the Rack Gear loses contact with the spur gear where the teeth have been removed, the slingshot is released flinging the game piece. As the spur gear continues to rotate, its teeth come in contact with the rack gears again to pull the track back, starting the cycle all over again.
The modified spur gear is sometimes called a slip-gear.
|Catapult using a Drop Off Cam||Catapult using Pneumatics|
Catapults throw game pieces with a lever arm. The game piece is placed on one side of the lever arm in a game piece holder and elastic bands or latex tubing are attached to the other side of the lever.
One way to assemble a catapult is to use a Drop Off Cam from the Advanced Mechanics and Motion Kit. A motor will rotate the cam which pushes the lever arm down and stretches the rubber bands. When the cam reaches the drop off point, it releases the catapult flinging the game piece. The cam can continue to rotate and repeat the cycle.
A pneumatic cylinder system can also be used to fire a catapult.