TEN-PIN
Source: Wikipedia
A very common design for ten-pin bowling (the Brunswick Model A, dating from 1955, as well as the developed A2 and JetBack versions of it) pinsetters work as follows.
First, the balls and pins are pushed off the end of the lane onto a shaking board the width of the lane. This "shaker" transfers the ball and pins to the rear of the pit, behind the lane's pindeck. Two large spinning wheels are situated with their common axis along the bowling lane. The ballwheel is the one closer to the bowler and is smooth on the inside; the pin-wheel (or pin elevator) has many pockets which capture the pins.
When a ball rolls back to the ballwheel, friction lifts the ball up to the side where it catches on two lift rods covered with a rubber material. Wedged in between, the ball is rolled upward. When it gets to the top, it is deposited onto a metal track which usually leads underground, and is pushed along by a long accelerator belt. Finally, the ball is pushed upward by two pulleys located at the head of the ball return track, where it is deposited.
When a pin rolls back, the smaller diameter of the pin allows it to fall rearwards through the ball return wheel. Still being shaken by the board, it bounces around until it lands in a pocket in the pinwheel. It may be seated in the pinwheel head-first or base-first. The wheel brings the pin to the top and drops it into a metal tray, called a "turnaround pan". It's shaped somewhat like a scoop, with the lip of the scoop facing the bowler. The weight of the pin's body makes it drop into the pan base-first. It orients the pin so that its base is coming toward the bowler. From there a conveyor belt lifts the pin up, letting it slide into one of ten spots in a rotating metal basket called the "turret". (situated just above the triangular-shaped deck, visible the bowler when the pins are set.) When a pin lands in an empty location in the turret, the turret rotates (or "indexes") so that the next pin will land in the next location, with the center of the turret also having an open location for the number 5-pin, at the center of the complete rack. Once the turret is full, the machine waits until it needs to re-set the pins. At that point, all ten pins are simultaneously dropped from the turret into the spotting table, which lowers them onto the lane.
This style of machine is typically loaded with 20 pins, though most proprietors normally put in 22 pins to facilitate quicker loading and faster operation of the pinsetter, especially in cases where the bowler(s) make two strikes in quick succession. Adding a couple of extra pins does not put undue stress on the machine, but adding more than that is not advisable due to damage that can occur to the machine. Other centers will only load the pinsetter with 19 pins. Having only 19 pins in the machine will cause fewer "stops" this is normally done by centers who don't take care of their property like they should. There is a drawback to 19 pins though, if stops do not occur problems will not be found until they become severe.
