Pulley cable or belt. The drive element of a pulley system can be a rope, cable, belt, or chain. Hero of Alexandria identified the "pulley" as one of six simple machines used to lift weights. Pulleys are assembled to form a block and tackle in order to provide mechanical advantage to apply large forces. Pulleys are also assembled as part of belt and chain drives in order to transmit power from one rotating shaft to another. A set of pulleys assembled so that they rotate independently on the same axle form a block. Two blocks with a rope attached to one
Off-tackle run ball carrier. The Maryland I used the 2nd back to lead through the hole and block the linebacker. More complicated versions of the play have pulling guards block the linebacker or combination blocks by a tight-end and tackle to create the hole and block the linebacker. The off-tackle play is a key feature of the single wing offense. Off-tackle run An off-tackle run in American football is a play in which the running back carries the ball through a running lane off of the tackle's block. The lead block kicks out the end man on the line of scrimmage, and