Behind the Scenes
Two other functions of the pinsetter that are not seen by the bowler are the ball accelerator and the pin elevator. The ball accelerator returns the ball to the bowler at the other end of the lane through a conveyor-like system.
After a roll, the ball and the knocked-down pins are located behind the lane in the ball pit. Below the ball pit is a conveyor belt called the transport band. The pins and ball fall onto this band and are moved toward the pin elevator. The bowling ball takes a detour at some point along the transport band, veering off through a specially designed ball door. Only the ball is heavy enough to trigger the sensor necessary to open the door, so only the ball can go through. The ball is then accelerated through a conveyor system under the lane, back toward the bowler for the next roll.
The pins on the transport band continue toward the pin elevator. The pin elevator consists of about a dozen trays located on two pulleys. The pins funnel onto the trays and are raised up toward the pin distributor. The distributor is located above the pin table. It helps place new pins into the pin table so they are ready when a new rack is needed.
The distributor has a mechanism known as a shark switch that pivots a funnel-like tray back and forth onto either of two conveyor belts. The position of the switch is determined by electronics in the pinsetter that know exactly where a new pin is needed. Each of the two conveyor belts has a number of pin stations where the pins settle into the pin table. The pins are kicked off the conveyor belt into the pin stations by bumper devices controlled by the main electronics (which determine where a pin is needed). Once the new pins are loaded, the pin table pivots horizontally, turning the bowling pins upright, and lowers them onto the lane at the proper time.
For lots more information on bowling pinsetters and related topics, check out the links below.