THE DESIGN
THE COMPONENTS
REVOLVING BALLOON INFLATOR
The revolving balloon inflator is comprised of a disk with 8 inflation nozzles. The inflation nozzle size was selected such that a balloon could easily slide over the tapered edge of the nozzle and could stay in place during inflation. The nozzle backs are threaded into custom NPT thread reducers, which allows the tubing between the solenoid valves on the manifold and the nozzle to be 1/4 inch in outer diameter. The stepper motor allows the revolver to reliably rotate a given angle. The motor bracket and standoffs are designed to help locate the revolver on the main assembly while providing clearances to all nearby components.
PNEUMATIC CLAMPS
The pneumatic clamps enable the balloon to be grabbed and manipulated through the rest of the mechanism. They accomplish this by using pressurized gas and valves to push the end of the piston. The output force of the piston can be calculated as the input pressure multiplied by the area of the bore of the piston. The clamps are designed so that as the piston extends a linkage is rotated and clamps the balloon onto a rubber pad for maximum friction. Using the linkage, the clamp assembly is able to transfer the force from the piston to the clamping pad. In the overall design, one of these clamps is fixed and the other is rotated by a motor.
LINEAR GUIDE & CARRIAGE
The linear guide allows for the carriage to move back and forth between the revolver and the balloon tie tool. The linear guide is operated by a belt pulley on the underside of the upper level of the assembly. The carriage contains two pneumatic clamps: one clamp is fixed to the side wall of the carriage, and the other clamp against the rear wall of the carriage is allowed to rotate with the use of a motor.
BALLOON TYING MECHANISM
The main functionality of the balloon tying mechanism is derived from the tying tool’s ability to travel upwards as well as rotate. This is accomplished with two motors. The upper motor controls the power screw, which allows the tying tool to move axially up and down. A wall stop is mounted onto the upper motor to prevent the tying tool from rotating relative to the upper motor as it moves axially. The lower motor rotates everything mounted above it. The ability to control both axial and rotational motion is crucial for allowing the mechanism to tie balloons successfully.
