Claws are usually attached to an end of an arm and are used for grasping an object. Motors or pneumatic systems are used to activate the claws. Motors are commonly used with a gear ratio or sprocket/chain system.
Single-sided and double-sided claws may use an increase torque gear ratio and roller claws may use an increase speed gear ratio.
Claws can be assembled using a variety of the Motion Products, the Structural Products, and the Other Products from the VEX metal product line. Rubber bands, latex tubing, and/or Anti-Slip Matting can be used to increase the grip on claws.
If time is available, several prototypes of claws should be developed during the design stage to assess which will be most effective for manipulating game pieces. Sometimes a simple claw design can be the most competitive.
Some common types of claws include:
Single-sided claw or sometimes called a clamping claw is typically assembled with a fixed piece of structural metal and a second piece structural metal attached to a motor/gear system.
The side of the claw activated by the motor, opens and closes, clamping the game piece against the fixed piece of structural metal.
Double-sided claw will activate both sides of the claw. Double-sided claws products are available with the VEX Claw Kit and the V5 Claw Assembly (which is presently included in the V5 kits).
Custom assembled double-sided claws typically have an even number of gears setup to move the two sides of the claw. One side of the claw will be attached to the first gear in the assembly and the second side of the claw will be attached to the last gear in the assembly, allowing the claw to open and close as the gears are rotated.
Roller Claws are typically assembled using Wheels, Intake Rollers, or Tank Treads. Roller claws function by spinning their rollers and having game pieces pulled into the claw. Then the rollers can be reversed, pushing them out.
Roller claws can be assembled with one side of the claw having a fixed piece of structural metal serving as a friction plate. The other side will have an active roller to roll the game piece in, along the fixed side. A roller claw can also be assembled with a roller on both sides of the claw.
Typically roller claws are designed to spin faster than the robot can move forward.
Roller claws allow game pieces to be picked up with less time aligning the robot, however, they require more time and planning to assemble.