A swing spring comprises a first plate or top, a second plate or bottom, guide rods extending between and connected to the first plate and the second plate, a third slider or slider plate slidable along an axis along the guide rods between the first plate and the second plate, a compression spring captured between the third plate and the second plate, a first hook rotatably coupled to the first plate by a thrust bearing and extending in a first direction along the axis, and a second hook coupled to the third plate and extending in a second direction opposite the first direction through the second plate.