US Patent 7866579 Spreader

A spreader (100) for spreading material, which in one embodiment comprises an upper bracket (120), a shaft (140), a return spring (160), a lower bracket (180), first and second sets of chain links (200a and 200b), and a spreader plate (220). The upper and lower brackets (120 and 180) are preferably aligned in the same vertical plane. The first and second chain links (200a and 200b) are located on opposite sides of the spreader (100) and on either side of the shaft (140). Upon rotation of the spreader (100) the first and second sets of chain links (200a and 200b) experience a centrifugal force sufficient to cause the spreader plate (220) to move down the shaft (140) and upon ceasing rotation the spreader plate (220) returns to a default position proximate to the top of the shaft (140).