Antispin device for a gyrating rock crusher including a stationary spindle (62) and a crusher head (36) driven by an eccentric (20) and running in a stationary crusher bowl (48). A clutch member (70) having a square crosssection fastened to the top of the spindle (62), and a polyurethane body (80) is fastened to the crusher head (36) and having a square opening (81) receiving the clutch ...