If you’re looking for a more thorough explanation of how a pinsetter works, this Pop Sci article from the same year is handy.

Automatic Pinspotter invented by Fred J. Schmidt, of Pearl River, N.Y., is shown here with its inventor. The machine employs mechanical, electrical and suction methods in its operation. It performs all phases of pit work, including setting pins, sweeping “deadwood” off the alley and returning the ball to the bowler. After the first ball is delivered the machine picks up the pins left standing, “sweeps” the alley and then returns the previously standing pins to their exact positions for the second ball. The photo at the left shows the intricate mechanism of the machine.

Ten-Pin Boys’ Work in Bowling Alley Done by Machine

A BOWLING alley with essentially no difference from a regulation type is in operation in Germany equipped with a machine that not only does the work of the ten-pin boy but also registers the count of the games and keeps the players’ scores separate. The machine is mounted under the ten-pin platform. It stands the pins up after they have been knocked down, returns the balls and tabulates the count by an illuminated indicator. It is electrically operated, and no further attention need be paid it after the current has been turned on. The pins are attached to the platform by knuckles which allow a ball to topple the pins if it strikes or grazes them.