Splocket

The screens are connected by chain belts and splocket wheels, so that the bottom screen drives the other two.

Source: wiktionary

Derailleurs, caliper brakes, drum brakes, three-speed hubs not incorporating coaster brakes, click twist grips, click stick levers, multiple freewheel splockets.

Source: wiktionary

1898, Frank William Macey, Specifications in Detail, pages 162⁽¹⁾ and 175⁽²⁾ ⁽¹⁾ Common and jack rafters…with cut wrought ends at overhanging eaves, and wrought splocket (cock) pieces. ⁽²⁾ See clauses Nos. 75, 77 to 89, and 91 to 99, for any other parts to the roof which may be required, such as tilting fillets, splockets, boarding, fascia, eaves soffits and other items.

Source: wiktionary

Sprocket, Splocket. A triangular piece of timber.

Source: wiktionary